<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Comparative Study of Tools for the Integration of Linked Open Data: Case study with Wikidata Proposal</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Roxana Martinez</string-name>
          <email>mariarmartinez@uade.edu.ar</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Gonzalo Pereyra Metnik</string-name>
          <email>gpereyrametnik@uade.edu.ar</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="editor">
          <string-name>PCWrEooUrckResehdoinpgs ISSNc1e6u1r-3w-0s0.o7r3g</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Universidad Argentina de la Empresa</institution>
          ,
          <addr-line>Buenos Aires</addr-line>
          ,
          <country country="AR">Argentina</country>
        </aff>
      </contrib-group>
      <fpage>237</fpage>
      <lpage>252</lpage>
      <abstract>
        <p>The approach of this work is based on a comparative analysis of several tools used for the management of linked open data. To do this, diferent sections are shown, initially an introduction to the topic is presented, identifying the importance of open data for people, and showing how the results generated through them can benefit. In addition, special emphasis is placed on the need for tools that facilitate both their interaction and manipulation. A section is also shown with related works on this topic, identifying previous studies that evaluated similar tools. The objective is the presentation of a comparative analysis of tools on the study of a proposed data model, which is used to perform tests with five selected tools: 1) API, 2) SPARQL in Wikidata Query Service (WDQS), 3 ) Pywikibot and 4) OpenRefine with the Wikidata plugin. The main task is to identify, for each tool, the evaluation in terms of its ability to integrate and manage Linked Open Data, its ease of use, and its performance in executing specific tasks. Finally, the results obtained in the performance of the analyzed tools are shown, allowing us to know the strengths and weaknesses of each one concerning the proposed data model. On the other hand, the ifndings of the study are presented that suggest recommendations for the selection of the most appropriate tool according to the specific requirements needed in aspects of data integration in a project.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Linked Open Data</kwd>
        <kwd>Wikidata</kwd>
        <kwd>SPARQL Wikidata Query Services</kwd>
        <kwd>Pywikibot</kwd>
        <kwd>OpenRefine</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <sec id="sec-1-1">
        <title>1.1. Context</title>
        <p>
          Linked data represents a set of good practices approved by the World Wide Web Consortium [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ],
designed for the publication of information on the web, thus facilitating communication between those
who share said information. “The integration of open access policies and linked data have generated
the position of Linked Open Data (also known as Linked Open Data or simply LOD)” [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ], these provide
a set of services for the publication of resources to through some technologies such as: SPARQL or LOD
API.
        </p>
        <p>
          One of the points worth mentioning as an important focus is that “LOD is often considered as a
virtual data cloud where anyone can access any data they are authorized to see and can also add data
without altering the original data source. This provides an open environment where data can be created,
connected, and consumed at Internet scale” [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ].
        </p>
        <p>
          The World Wide Web Consortium [
          <xref ref-type="bibr" rid="ref1">1</xref>
          ] “recommends the use of URIs (Uniform Resource Identifiers)
and HTTP URIs to access information about resources through a data exchange model such as RDF
(Resource Description Framework). In addition, it proposes incorporating other links, as a complement,
to the use of an RDF triplet query language. For example, SPARQL, which is recommended by the W3C”
[
          <xref ref-type="bibr" rid="ref4">4</xref>
          ]. These recommendations are shown in the international publication of Good Practices for Linked
Open Data [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ], along with some technical aspects to consider for the implementation of this technology.
Many authors agree that this new trend could incorporate numerous benefits, for example, according to
Berners-Lee [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ], LOD is based on the principles of the semantic web. It uses technologies such as RDF
and URIs to establish specific connections between diferent data sets, thus facilitating its interoperability
and reuse that could improve government management in matters of Social Development for diferent
citizens. Linked open data is published, consumed, and managed by multiple organizations around the
world, thus generating new possibilities for the analysis of large volumes of information.
        </p>
        <p>
          On the other hand, there are diferent linked open data repositories, one of the best known is
Wikidata [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ]. This repository allows various users to work with wiki-like features and is managed
by the Wikimedia Foundation. An interesting feature in this context is that it is not necessary to
dynamically update the content of each wiki, since there is common data, for example, statistics, dates
or locations that can be centralized and related through the Wikidata platform, thus generating, a
collaborative approach. In addition, specific information on some relevant considerations for data
processing, scripting, tools, and other resources to consider when processing linked open data is
presented on its oficial website [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ]. Wikidata stands out for its great potential in interoperability and
its ability to connect data from various domains. This great ability to link information eficiently is
what makes it one of the most powerful tools in the technological environment. On the other hand, its
potential is exploited by researchers, programming developers, and organizations that use these good
practices to create advanced applications, driving progress in the field of knowledge and technology.
        </p>
        <p>
          As a last point to comment on, Wikidata has a wide thematic coverage that allows the integration
of multiple data sources, this allows for generating a great benefit between the semantic connections
that could be made and also enriches the interoperability between diferent data sets [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ]. This feature
gives users the ability to extract data that can be processed and obtain information that could be
interconnected to obtain significant value. The latter takes on fundamental value in this context since
it allows the heterogeneity of the data to be eficiently managed and at the same time maintains the
quality of the linked information. These are fundamental points when it comes to data integration
because they need to be accurate and functional. This technique is crucial to guarantee the linking
of data, maintaining both its content and its integrated metadata so that they can be combined and
used [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]. That is why it is necessary to take full advantage of Wikidata’s ability to manage these
characteristics, in aspects of collaborative knowledge.
        </p>
      </sec>
      <sec id="sec-1-2">
        <title>1.2. State of the art</title>
        <p>In recent years, various solutions and tools have been developed for the integration of linked open data.
These tools have similar and diferent characteristics, for example: the use of APIs, consultation services,
and plugins, among others. Although notable progress has been made, challenges remain, including
data heterogeneity, quality of integration, and usability of tools. Previous research has explored diferent
aspects of these solutions, providing a basis for understanding the current strengths and limitations in
this field.</p>
        <p>
          It is worth mentioning that several repositories and projects are important in the LOD context, such
as DBpedia works with the extraction of structured data from Wikipedia and converts it into a set of
Linked Open Data. DBpedia is used for applications that require general information and is one of the
ifrst initiatives in LOD. Although there are several investigations [
          <xref ref-type="bibr" rid="ref11 ref12">11, 12</xref>
          ], it stands out for working
with assignments that are created through a global collaborative efort and allow combining knowledge
from the diferent editions of Wikipedia.
        </p>
        <p>
          Another repository is GeoNames, there are several works [
          <xref ref-type="bibr" rid="ref13">13</xref>
          ] in which they use this as a geographic
resource that provides place names and coordinates, used in applications that require linked geographic
information. For example, using a methodology to semi-automatically generate a tourism knowledge
graph (TKG), which can be used to support a variety of intelligent services in this space, and a new
ontology to model this domain, the analysis ontology tourism (TAO). Another work is presented by
Brandt [
          <xref ref-type="bibr" rid="ref14">14</xref>
          ], which uses resources related to LOD and repositories such as Geonames and DBpedia for
semantic improvement. The study allows us to conclude that the making available of government data,
especially legislative data, can be done following the recommendations and good practices of the W3C.
        </p>
        <p>
          Another notable repository is LinkedGeoData, which features a project that converts OpenStreetMap
data into LOD, allowing geospatial information to be queried and used alongside other linked data.
Several works indicate that with indicated redesigns it is possible to consult these data sets in English,
German, French, Italian, and Spanish, among others [
          <xref ref-type="bibr" rid="ref15 ref16">15, 16</xref>
          ]. As mentioned above, there are several
repositories, this work will be based on the study of Wikidata because it stands out in this context for its
great interoperability and the large community that supports it, but it is necessary to understand that
the choice of a reference in LOD depends on the specific context and needs of the project in question.
        </p>
      </sec>
      <sec id="sec-1-3">
        <title>1.3. Motivation and Objective of the Study</title>
        <p>
          Although significant progress has been made in the availability of Linked Open Data, the integration
and management of this data remain considerable challenges. The large amount and diversity of data
available can cause problems such as format incompatibilities, variations in data quality, and dificulties
in synchronizing information between diferent sources [
          <xref ref-type="bibr" rid="ref17">17</xref>
          ]. These shortcomings mentioned above
can limit the great benefits of interconnecting linked open data, which could make a correct analysis of
the information impossible. For this reason, it is essential to have tools that facilitate the integration of
this data from multiple data domains, in addition, it must be ensured that the quality and metadata are
consistent between the linked information. This need to have efective solutions is increasingly vital
since open data today continues to grow not only in large quantity but also in great variety, which makes
it more necessary to have eficient tools to take advantage of these resources. These tools must be well
designed and tested to significantly improve the ability to manage this linked open data since incorrect
data or data that does not maintain quality in its presentation could encourage the development of
applications with erroneous information.
        </p>
        <p>The objective of this work is to analyze various tools used for the integration of Linked Open Data.
The study seeks to evaluate the performance of these tools in diferent aspects, for this, a data model
proposed by the authors was designed. Basically, four specific tools that present great potential in
aspects of interaction with Wikidata will be analyzed: 1) the Wikidata API; 2) the SPARQL in the
Wikidata Query Service (WDQS); 3) Pywikibot; and 4) OpenRefine with its Wikidata plugin. Also, this
work will identify the strengths and weaknesses of each tool in terms of its ability to integrate and
manage linked data, as well as its ease of use and performance on specific tasks. Through this tool
evaluation, the authors provide good practice recommendations for selecting the most appropriate tool,
which presents specific data integration requirements in future projects.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. Methodology</title>
      <p>To carry out the analysis of the indicated tools, a work methodology is presented that includes the
selection of the tools, with the explanation of the most relevant characteristics of each one. On the
other hand, the definition of the evaluation metrics that will be considered for this study is presented.
Below is a comparison of each of these allowing an analysis of their most relevant functionalities, as
well as their limitations.</p>
      <sec id="sec-2-1">
        <title>2.1. Tool Selection Criteria</title>
        <p>Wikidata is considered one of the most important sources of structured data on the web. It was developed
in order to promote adequate access and manipulation of this type of data. For this technology, the
use of APIs that allow interaction with direct queries for this linked data structure stands out. In
addition, SPARQL query services are incorporated, such as Wikidata Query Service (WDQS), and
automation tools such as Pywikibot. These types of technologies are specialized, such as Wikidata
Toolkit (WDTK), because they ofer eficient solutions for the management of large volumes of data,
while applications such as OpenRefine, with its Wikidata complement, allow data processing, along with
analysis techniques. data cleaning. For the latter, a great advantage is that they can be very accessible
to users without programming experience.</p>
        <p>This research will analyze four tools that correspond to the context of Wikidata: 1) the Wikidata
API; 2) the SPARQL in the Wikidata Query Service; 3) Pywikibot; and 4) OpenRefine with its Wikidata
plugin. These have been selected for their relevance and applicability in the integration of Linked Open
Data (LOD), in addition to their ease of use and their ability to eficiently handle data manipulation
tasks in contexts where large volumes of data are not required. Regarding the selection of the SPARQL
API and the query service, they were considered since they are fundamental for the extraction and
manipulation of data in Wikidata. On the other hand, Pywikibot was considered because it stands out
in the automation of repetitive tasks, and finally OpenRefine, for being a powerful platform in aspects
of data cleaning and transformation, thus guaranteeing the quality and consistency of the information
linked.</p>
        <p>Finally, for this study, it was decided to eliminate Wikidata Toolkit (WDTK) because, although it is a
powerful tool for executing complex SPARQL queries and handling large volumes of data, this study
focuses on solutions that are targeted to contexts for a data model proposed simple, so the data volume
is not that significant. Additionally, WDTK is designed to manage and process large amounts of RDF
data, which exceeds the needs of our analysis, which focuses on integrating and manipulating data at a
more manageable scale. By opting for tool styles such as the Wikidata API, SPARQL in Wikidata Query
Service, Pywikibot, and OpenRefine with its Wikidata plugin, the study seeks to ofer a more practical
and common application-oriented perspective on Linked Open Data integration, without the additional
complexity that these more advanced tools would handle.</p>
      </sec>
      <sec id="sec-2-2">
        <title>2.2. Tools Description</title>
        <p>This section indicates a study of some of the most relevant works on the technical aspects of each of
the tools used.</p>
        <p>
          Wikidata API: Allows access to Wikidata data through HTTP requests, obtaining data in diferent
formats such as JSON or XML. Wikidata uses the Stories Services API to generate multimedia stories
related to people, organizations, and periodicals [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ]. Application developers today have three options
for exploiting the knowledge present in Wikidata: they can download Wikidata dumps in JSON or
RDF format, they can use the Wikidata API to obtain data about individual entities, or they can use
the Wikidata SPARQL endpoint Wikidata [
          <xref ref-type="bibr" rid="ref19">19</xref>
          ]. There is also research on the gene-drug interaction
database as a web resource that provides information on gene-drug interactions and selectable genes
from publications [
          <xref ref-type="bibr" rid="ref20">20</xref>
          ].
        </p>
        <p>
          SPARQL Query: Query service that allows you to access and manipulate data stored in RDF (Resource
Description Framework) format through the use of SPARQL, a query language standardized by the
W3C. Some works present how Wikidata is integrated into the Linked Data Web and how the SPARQL
Query Service facilitates consultation and access to linked data. Other studies show how Wikidata
provides a SPARQL access point, allowing users to perform complex queries on an open data set. This
not only improves Wikidata’s interoperability with other linked datasets on the semantic web, but
also allows researchers and developers to exploit Wikidata information [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ]. Another study focuses on:
Implementation of a current research information system (CRIS) that uses semantic technologies to
integrate and manage data from various sources in the university environment. This system allows
advanced queries through a SPARQL Point, which facilitates the retrieval of structured and detailed
information on scientific production [
          <xref ref-type="bibr" rid="ref21">21</xref>
          ].
        </p>
        <p>
          Pywikibot: Bots and automation tool for interacting with Wikidata and other Wikimedia projects.
There are research papers that delve into topics such as wiki projects, voluntary contributions, notable
Python contributions, an overview of PAWS (Python Data Science Environment for Jupyter) and
PyWikiBot [
          <xref ref-type="bibr" rid="ref22">22</xref>
          ]. Another study focused on the work presents an overview of the Chinese Wikiproetas
project, using OpenRefine and PyWikibot to improve the names of more than 4,000 Chinese women
poets in Wikidata with great contributions of technical aspects for the use of this tool [
          <xref ref-type="bibr" rid="ref23">23</xref>
          ].
        </p>
        <p>
          OpenRefine with Wikidata plugin: Data cleansing and reconciliation tool with the ability to link
local data to Wikidata. Data in OpenRefine can be easily transformed into Wikidata declarations by
creating a dedicated export schema that maps each column to respective elements and properties. Some
works show several preparation techniques for processing directly with QuickStatements, allowing
editing and creating Wikidata elements directly from OpenRefine [
          <xref ref-type="bibr" rid="ref24">24</xref>
          ]. Another study proposes
generating a repository with an open database for academic publications using Wikidata with OpenRefine
technology [
          <xref ref-type="bibr" rid="ref25">25</xref>
          ].
        </p>
        <p>As mentioned in other sections, there are many notable features of each of the tools mentioned,
these relate to the Wikidata API allowing developers to interact with Wikidata, and providing access to
read, write and query data. In addition, it facilitates the management of Wikidata elements, properties
and descriptors, integrating tasks such as the creation and modification of elements, data search, and
retrieval of structured information in formats such as JSON and XML. On the other hand, SPARQL
Query Service presents a service that allows complex queries to be performed on RDF data using the
SPARQL language. Additionally, it ofers the ability to search for specific patterns, filter results, and
combine information from multiple linked data sources. This service allows the use of data in formats
that are compatible with diferent applications and also allows data reading and modification operations,
which allows adequate interoperability. Pywikibot works with Python, it was designed to automate
interactions with MediaWiki, including Wikidata. It also allows the creation of scripts to perform
repetitive tasks, update elements, and manage data, making it easier to maintain Wikidata content.
Finally, OpenRefine with Wikidata Plugin is a data cleansing and transformation tool, which can be
used with Wikidata data. This plugin facilitates the identification of various objects, adds characteristics
to them and updates the data referring to them.</p>
      </sec>
      <sec id="sec-2-3">
        <title>2.3. Evaluation Metrics</title>
        <p>This section presents the evaluation metrics that were considered to analyze and compare the diferent
selected tools. Criteria have been selected for an evaluation that includes technical aspects and also
its ease of use in aspects of extraction and processing of linked data. In addition, measurements are
made in aspects of data access speed, response times, and eficiency in information retrieval. Another
important point that is considered is interoperability, which examines the ability of tools to interact and
be compatible with other software. The scalability of each tool is also studied, considering the growing
volume of data and users who use it. Finally, it is analyzed what support each tool provides in technical
aspects in terms of help resources and its activity in the Community of users and programmers.</p>
      </sec>
      <sec id="sec-2-4">
        <title>2.4. Proposed LOD model</title>
        <p>Figure 1 shows the data model proposed by the authors, it shows the relationship between the diferent
objects related to educational and geographical aspects using the ontology and properties of Wikidata.
The hierarchical and spatial relationship of universities such as the “Universidad Privada del Valle” and
the “UADE” (Argentine Business University) with their respective countries, Bolivia and Argentina, is
highlighted, using the country property (P17). Furthermore, the entity of Buenos Aires is represented as
the capital of Argentina through capital ownership (P1376) and as an instance of an Argentine city. It also
illustrated how Argentina and Bolivia are part of a larger entity, “Latin America,” using the ownership
of part of (P361). This model not only connects educational institutions to their administrative and
political locations but also places these locations in a broader regional context, thus demonstrating the
ability to link data across diferent levels of geographic and thematic granularity.</p>
        <p>This proposal, as an example, is a data model that not only allows for a clear and structured
understanding of the relationships between diferent educational and geographic entities but also facilitates
data interoperability in a broader context. By leveraging the ontologies and properties of Wikidata, a
coherent and linked representation of information is achieved, which can be used in various applications,
from academic research to the development of geographic information systems (GIS).</p>
      </sec>
      <sec id="sec-2-5">
        <title>2.5. Testing Procedure</title>
        <p>With the proposed linked open data model and the tools selected for study analysis, the testing procedure
to be carried out will be carried out. That is, the methodology used to evaluate and validate the tools
and technologies considered in this study consisted of a series of steps that allow simulating real-use
scenarios with the proposed data model, allowing performance to be measured and compared using the
metrics previously established in the previous section. Initially, test environments were set up, ensuring
that all tools were correctly installed and updated. Data extraction and access tests were then carried
out using standard data sets, measuring ease of use and response speed. Execution times were recorded
and the tool’s ability to handle output conversions to diferent formats was observed. Subsequently,
the interoperability of the tools concerning other software was analyzed, as well as scalability aspects
through diferent tests. Finally, studies were obtained on the technical support provided on public
websites, which would allow finding solutions to possible problems; some of the sites analyzed were
Internet forums.</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3. Results</title>
      <p>This section analyzes the main results obtained during the evaluation of the tools studied. This analysis
presents the main benefits and limitations of each tool. Below are detailed: a) comparison of tools; and
b) comparative analysis.</p>
      <sec id="sec-3-1">
        <title>3.1. Comparison of Tools</title>
        <sec id="sec-3-1-1">
          <title>3.1.1. Wikidata API</title>
          <p>
            For the wiki data API, some techniques were used that provided advantages when using it. The Wikidata
REST API [
            <xref ref-type="bibr" rid="ref26">26</xref>
            ] provides a simple and eficient interface for performing quick queries and obtaining
structured data from Wikidata, which is ideal for developers looking to integrate data eficiently. As for
what you respect about the documentation provided for this API, API REST the Wikidata in Javascript,
looks at a set of advanced functionalities that are developed on its website, and that are explained
for integration with Javascript technology. The Wikidata REST API manual in PHP helped provide
information on a fluid integration of Wikidata functions in systems based on this language. Finally,
Wikidata’s Stable Interface Policy [
            <xref ref-type="bibr" rid="ref27">27</xref>
            ] helped to understand how to guarantee that the interfaces and
APIs used will remain stable over time, providing security and confidence to developers by ensuring
that their applications will not be afected. due to unexpected changes in the API. Below is a qualitative
analysis of the aspects considered by each tool:
          </p>
          <p>[Documentation] Clarity and Complexity: The documentation is well structured and clear for
experienced users but can be overwhelming for beginners. RDF and JSON-LD are not suficiently explained
to users. Examples of use: The examples shown are useful, but they are very simple. Additionally, there
is a lack of guidance on query optimization. Finally, the documentation is not located in one place but
is spread across multiple sources.</p>
          <p>[Ease of use for data extraction] Learning curve: The API is intuitive for programmers dealing
with RESTful APIs but is very complex for users without prior experience in Wikidata or RDF. Another
point to keep in mind is that there are no graphical interfaces that facilitate its use. Ease of access to
complex data: API allows access to complex data. Tool compatibility: It is compatible with data analysis
tools such as Python, but its integration is not simple.</p>
          <p>[Data access speed] Average Latency: The Wikidata API ofers fast response times for simple queries.
Performance under load: API can exhibit poor performance when performing very complex queries.
There aren’t many options to optimize the speed of these queries, which can be a problem in applications
that require real time access.</p>
          <p>[Ease of output conversion] Available Formats: The API allows you to obtain data in JSON,
RDF, and XML formats, which provides greater flexibility in the use of diferent applications. Ease of
transformation: JSON is one of the most compatible formats with other applications, but converting
from RDF may require specialized knowledge, as RDF can be complicated to handle.</p>
          <p>[Interoperability] Compatibility with Standards: The API uses standards such as RDF and
JSON-LD, making it easy to integrate with other Linked Open Data (LOD) systems. Integration API:
Supports other LOD APIs and services, allowing you to combine data from multiple sources for more
complete analysis.</p>
          <p>[Escalabilidad] Request Limits: The API has limits on the number of requests per second to prevent
overloading, which can be an issue in large-scale applications. Scalability management: The API is
suitable for small and medium-sized applications. Support for large volumes of data: It can handle large
volumes of data, but with performance that decreases under high concurrent demands.</p>
          <p>[Support and community] Technical Support Availability: Wikidata has adequate technical support,
but the majority of support comes from the user community. Community Resources: There are active
forums, mailing lists, and community resources that are valuable for resolving common questions and
problems. Documentation Updates: Documentation and resources are not updated regularly, and support
can be slow and highly dependent on community participation.</p>
          <p>[License and terms of use] License Type: The Wikidata API operates under the Creative Commons
CC0 1.0 license, allowing unrestricted use of the data. Use Restrictions: There are no significant
restrictions, allowing free redistribution and modification of the data, which is ideal for open projects.
Rights and Obligations: Users are required to follow the rules of the CC0 license but are free to use the
data in commercial or noncommercial applications without the need for attribution.</p>
          <p>A small prototype was developed that is prepared to interact with the proposed data model, in addition,
it is designed to interact with Wikidata through its REST API. Defines lists of subject identifiers and
relevant predicates (such as universities and countries) for performing RDF queries. Use the requests
library to make API requests and rdflib to handle the resulting RDF data. In the Figure 2 shows how
an RDF graph is developed and manipulated using Python and the rdflib library. The code begins by
importing the necessary libraries (requests, time, and rdflib), which are essential for making HTTP
requests and handling RDF data. Below are identifiers (subject_ids) corresponding to specific entities in
Wikidata, such as “University” (Q3918), “Universidad Privada del Valle” (Q9091606), “Bolivia” (Q750),
“UADE” (Q3028249), “Argentina” (Q414), “Buenos Aires” (Q1486), “City of Argentina” (Q5770918)
and “Latin America” (Q12585). These entities represent nodes in the RDF graph that models the
relationships between universities and their geographic and political locations. The model shows how
the relationships between these entities are structured using Wikidata properties, such as: “Country”
(P17), “Part of” (P361), “Capital of” (P1376) and “Instance of” (P31). In this context, the source code
allows the creation and use, through a graph, of data connections, access to queries, and analysis of
these. This approach is valuable for organizing and linking information about educational entities, and
their geographic and political context in a structured and easy-to-use way.</p>
        </sec>
        <sec id="sec-3-1-2">
          <title>3.1.2. SPARQL in Wikidata Query Service (WDQS)</title>
          <p>
            For SPARQL in Wikidata Query Service (WDQS), various techniques were used that ofer specific
advantages depending on their application [
            <xref ref-type="bibr" rid="ref28">28</xref>
            ]. The source code that builds the RDF graph is made
from Wikidata entities and properties, which is useful in the context of SPARQL queries in Wikidata
Query Services [
            <xref ref-type="bibr" rid="ref29">29</xref>
            ], because it allows you to structure and organize Wikidata data in a standardized
format that is compatible with SPARQL. By transforming entities and relationships into RDF triples,
this code facilitates the creation of SPARQL [
            <xref ref-type="bibr" rid="ref30">30</xref>
            ] queries that can be run on Wikidata to extract, analyze,
and visualize complex information. In essence, it allows Wikidata data to be queried more eficiently
and accurately through SPARQL, which is essential for any type of analysis or application that relies on
linked data.
          </p>
          <p>[Documentation] Clarity and Complexity: The SPARQL query service documentation on Wikidata
is comprehensive and explains in detail how to use SPARQL to perform complex queries. It includes
an introduction to SPARQL, but due to the inherent complexity of this query language, it can be
intimidating for novices. Usage Examples: The documentation provides numerous query examples
covering a wide range of use cases, which is very helpful in understanding how to structure specicfi
queries. Coverage: The documentation covers almost all aspects of using SPARQL, from basic to more
advanced queries, including how to optimize queries to improve performance. However, some specific
use cases, such as manipulating complex results, are not fully detailed.</p>
          <p>[Ease of use for data extraction] Learning Curve: SPARQL is a powerful language but has a steep
learning curve. Understanding both SPARQL and the structure of data in Wikidata is necessary to
perform efective queries. Ease of access to complex data: WDQS is efective in accessing complex and
interrelated data. That is, it allows complex queries that combine multiple entities and properties. Tool
Support: SPARQL query results can be exported in various formats (such as JSON, XML, CSV), making it
easy to integrate with data analysis and visualization tools. However, building and maintaining complex
queries may require additional optimization and visualization tools.</p>
          <p>[Data access speed] Average Latency: Response time is fast for simple queries. However, latency
can increase significantly with complex queries. Performance under load: WDQS has some performance
issues when performing very complex queries. Sometimes the service imposes limits on the queries that
can be performed to avoid system overload. Optimization mechanisms: The documentation includes
suggestions for optimizing queries, but optimization requires a deep understanding of both SPARQL
and the structure of the data in Wikidata.</p>
          <p>[Ease of output conversion] Available Formats: Various formats can be used, JSON, CSV, XML
among others. This facilitates its use in diferent applications and analyses. Ease of transformation: JSON
and CSV are easy to handle and transform, making it easy to integrate into other analysis tools. However,
transforming complex SPARQL data queries into simpler structures can be a challenge. Compatibility:
The formats are compatible with standard data analysis tools. Handling more complex formats, such as
RDF, may require specialized knowledge.</p>
          <p>[Interoperability] Standards Compatibility: SPARQL is an accepted standard for queries on RDF
data, ensuring its compatibility with other Linked Open Data (LOD) systems and services. Integration
API: WDQS can be easily integrated with other services and APIs that support RDF and SPARQL,
making it easy to exchange data between diferent platforms. Interoperability Protocols: WDQS supports
standard interoperability protocols.</p>
          <p>[Scalability] Request Limits: The service has limits on the size and complexity of queries to avoid
overloading, which can be a drawback in projects that require complex queries. Scalability management:
WDQS is suitable for small and medium-scale queries. Support for large volumes of data: Although it is
possible to handle large volumes of data, performance can be significantly afected.</p>
          <p>[Support and community] Technical Support Availability: Wikidata provides adequate technical
support through its user community, but direct support is limited. Community Resources: There is an
active community with forums and mailing lists where users can share solutions and advice, which is
very valuable in solving common problems. Documentation Updates: Documentation and community
resources are updated periodically.</p>
          <p>[License and terms of use] License Type: Data obtained through SPARQL queries in WDQS are
subject to the Creative Commons CC0 1.0 license, allowing unrestricted use. Restrictions on Use: There
are no significant restrictions, allowing free redistribution and modification of the data. Rights and
Obligations: Users are required to follow the rules of the CC0 license but are free to use the data in
commercial or noncommercial applications without the need for attribution.</p>
          <p>Figure 3 shows the source code shows how to perform a SPARQL query through the SPARQLWrapper
library to extract data from Wikidata. The query result is presented as a list of triples, where each triple
contains a subject, a predicate, and an object, represented by their identifiers in Wikidata (such as ’Q414’
for Argentina or ’P17’ for "country"). These triples describe relationships between entities in Wikidata,
allowing us to understand how they are connected. The code also sets up a custom User-Agent header
to avoid being blocked by the Wikidata query service.</p>
        </sec>
        <sec id="sec-3-1-3">
          <title>3.1.3. Pywikibot</title>
          <p>
            Some sources are used as a study to carry out the test with a developed prototype [
            <xref ref-type="bibr" rid="ref31 ref32">31, 32</xref>
            ]. Below is the
analysis carried out for the Pywikibot tool.
          </p>
          <p>[Documentation] Clarity: Pywikibot’s documentation is detailed and well structured, although it
can be confusing for beginners due to the number of MediaWiki and Wikidata commands/functions.
Complexity: The documentation is primarily intended for experienced developers. It’s not as friendly
for users just starting with Python or Wikidata. Coverage: It is broad and covers most of the functions
that Pywikibot ofers, from editing pages to manipulating data in Wikidata. However, it can be dificult
to find specific documentation on optimizing scripts or handling large volumes of data.</p>
          <p>[Ease of use for data extraction] Learning Curve: Learning is complex, especially for those who are
not familiar with Python or Wikidata. Access to complex data: Pywikibot allows access to complex data
from Wikidata but requires advanced knowledge to create eficient scripts. Compatibility: Pywikibot
supports Python and can integrate with other tools. However, it is often necessary to transform the
data to adapt it to these tools.</p>
          <p>[Data access speed] Latency: The speed of data access may vary depending on the complexity of
the operations performed by Pywikibot. For simple tasks, latency is low. Performance: Pywikibot may</p>
          <p>Figure 4 shows the development carried out by the authors of this work, which shows the fragment of
a small prototype with the Pywikibot library to interact with Wikidata and perform queries that return
RDF triples, which are made up of a subject, a predicate and an object. Pywikibot is a collection of
Python tools that makes it easy to automate tasks on MediaWiki-based wikis, such as Wikidata. In this
code, queries are run to get and display specific relationships between Wikidata entities, represented by
their unique identifiers (such as ’Q9091606’ and ’P31’). These relationships are printed to the console,
showing the connections between diferent entities in the format of triples. The code is useful for
performing automated tasks in Wikidata, such as extracting and analyzing structured data for specific
research or applications.</p>
          <p>[License and terms of use] License: Pywikibot is available under the MIT license, allowing flexible
and free use of the code. Restrictions: There are no significant restrictions on the use of Pywikibot.
Developers are free to modify and redistribute the code. Obligations: Users must comply with the terms
of the MIT license but are free to use Pywikibot in commercial and noncommercial projects.</p>
        </sec>
        <sec id="sec-3-1-4">
          <title>3.1.4. OpenRefine with the Wikidata plugin</title>
          <p>
            To carry out an analysis of OpenRefine with the Wikidata plugin based on the points you mentioned,
some sources were worked with [
            <xref ref-type="bibr" rid="ref33 ref34">33, 34</xref>
            ]. Below is the analysis carried out:
          </p>
          <p>[Documentation] Clarity and Complexity: The OpenRefine documentation with the Wikidata plugin
is quite accessible and designed for users of diferent experience levels. Tutorials and examples are
provided to allow beginners to quickly familiarize themselves with the functionalities. Coverage: The
documentation covers a wide range of functionality, from installing the plugin to running SPARQL
queries. However, it may lack advanced details for users who wish to perform complex data
transformations. Examples of Use: There are practical examples that cover basic cases and some more complex
ones, but examples for more specialized scenarios may be lacking.</p>
          <p>[Ease of use for data extraction] Learning Curve: OpenRefine is intuitive, especially for users
who already have experience in data cleaning and transformation. The Wikidata plugin makes it easy
to integrate data without requiring advanced SPARQL knowledge. Ease of Access to Complex Data:
Although the use of the tool allows us to simplify data extraction, performing advanced queries is more
complex. Tool compatibility: It is compatible with multiple data analysis tools and its integration with
Wikidata allows easy access to large volumes of structured data.</p>
          <p>[Data access speed] Average Latency: Data access speed is good for simple queries. Performance
Under Load: There may be slowdowns when performing multiple complex operations or when working
with large volumes of data. Optimization Mechanisms: OpenRefine allows some optimizations to be
performed on queries, but most of the performance depends on the complexity of the SPARQL query.</p>
          <p>[Ease of output conversion] Available Formats: Extracted data can be exported in various formats,
including CSV, Excel, JSON, and others, making it easy to use in various applications. Ease of
Transformation: Data transformation is one of the strengths of OpenRefine, allowing personalized adjustments
according to the user’s needs. Compatibility: The export formats are widely compatible with other
analysis and visualization tools.</p>
          <p>[Interoperability] Standards Support: OpenRefine follows open standards and is compatible with a
wide range of Linked Open Data (LOD) tools, especially the Wikidata plugin. Integration APIs: Integrates
well with open data APIs, making it easy to combine data from multiple sources. Interoperability Protocols:
Compatible with standard protocols, allowing its use in environments that require interoperability with
other open data systems.</p>
          <p>[Scalability] Request Limits: OpenRefine itself does not impose significant limits, but the load on the
Wikidata API can be a limiting factor, especially if many requests are made simultaneously. Scalability
Management: It is suitable for small and medium-sized projects but may not scale well without careful
optimization for large volumes of data. Support for Large Data Volumes: Handles large data sets well,
but performance may decrease under very high loads.</p>
          <p>Figure 5 shows the OpenRefine interface, with the result of a data connection operation with Wikidata.
You see a table with 8 rows, detailing diferent entities such as universities, countries, and cities, along
with their properties (for example, "instance of" or "country") and corresponding values in Wikidata. On
the left, you can see the filtering and facet options, where entity judgment facets and the best candidate
score have been applied.</p>
          <p>[Support and community] Technical Support Availability: OpenRefine has an active community,
and support for the Wikidata plugin is primarily provided by users and developers in the community.
Community Resources: There are a good number of resources, including forums, mailing lists, and guides
created by the community. Documentation Updates: Documentation is updated regularly, although it
may depend on community participation to stay up to date.</p>
          <p>[License and terms of use] License Type: OpenRefine is open source, allowing its use and
modiifcation without significant restrictions. The Wikidata plugin is also under a permissive license. Use
Restrictions: There are no significant restrictions on its use. Rights and Obligations: Users can use and
modify the software under the Open Source license, with the obligation to follow the terms of the
corresponding license (generally GPL or similar).</p>
        </sec>
      </sec>
      <sec id="sec-3-2">
        <title>3.2. Analysis</title>
        <p>This work presented the analysis of four tools for the use of open data linked through a proposed data
model.</p>
        <p>The analysis of these tools was based on: a) Wikidata API, b) the SPARQL query service using
Wikidata Query Service (WDQS), c) Pywikibot, and d) OpenRefine with its Wikidata plugin. From
the Wikidata API point of view, this is an interesting option for integrating simple data queries, as it
ofers an easy-to-use RESTful interface for programmers with experience in this type of API. However,
you may be limited when performing more complex queries. On the other hand, it was observed that
SPARQL, through the Wikidata Query Service, is a very useful tool for performing complex queries on
interrelated data in Wikidata. Although its use requires a good knowledge of RDF and the Wikidata
data structure, this tool allows you to analyze data with a very good level of precision in its results. The
next tool analyzed is Pywikibot, it works with Python that ofers great flexibility to automate tasks
in Wikidata. It is ideal for handling large volumes of data. However, its use requires a high level of
knowledge in programming and Wikidata structure. Finally, OpenRefine with the Wikidata plugin is
presented as a tool that presents great advantages in data cleaning techniques, integrating data sets
linked with Wikidata. This tool is especially useful for those looking to improve the quality of their
data before incorporating it into deeper analysis. However, its learning curve can be steep.</p>
        <p>In terms of documentation and ease of use, all four tools feature extensive documentation, although
some stand out more than others. The Wikidata API and SPARQL are well documented, but their level
is complex for inexperienced users. Pywikibot, although it presents documentation, requires advanced
programming knowledge. OpenRefine, with its graphical interface, is more accessible for data cleaning
tasks, but its Wikidata plugin may require additional learning.</p>
        <p>The learning curve of these tools is very varied. The Wikidata API is relatively easy to use for those
with experience in RESTful APIs, while SPARQL requires in-depth knowledge of its programming
syntax, and in dealing with the data structure in Wikidata. On the other hand, Pywikibot features
a complex level of programming, and OpenRefine, while generally accessible and friendly, can be
complex to use when used in conjunction with the Wikidata plugin for advanced tasks. In terms of
performance, the Wikidata API and SPARQL ofer fast responses for simple queries, although they may
face limitations on complex queries. Furthermore, Pywikibot has problems in operational performance
aspects, since its eficiency depends on the optimization of the source code. OpenRefine is very eficient
for data cleaning, but its performance may decrease with large volumes of data.</p>
        <p>In terms of interoperability and flexibility, SPARQL and Pywikibot stand out for their high
compatibility with other Linked Open Data (LOD) systems and standards. The Wikidata API easily integrates with
other tools using RESTful calls, and OpenRefine, through its Wikidata plugin, provides a robust way to
link external data with entries in Wikidata. Community support for these tools is robust, facilitating
problem-solving and knowledge sharing. However, for users who require quick or specialized technical
support, relying exclusively on community support can be a challenge, especially in the case of SPARQL,
Pywikibot, and the OpenRefine plugin, where the technical complexity is greater. All tools operate
under the Creative Commons CC0 1.0 license, allowing free use of data for academic and commercial
projects. However, such a permissive license could raise ethical dilemmas related to data attribution.</p>
        <p>As for a quantitative analysis, estimates and measurements were made with the tools worked on.
Figure 6 shows a comparative graph of the graph creation times and development times for the diferent
tools. For the graph on the left, the graph creation times are shown in milliseconds, where OpenRefine
is estimated at an average of 4000 ms, being faster than Pywikibot (4665.79 ms) but slower than SPARQL
(632.03 ms). The Wikidata API (6747.69 ms) is also located at an average time, which places it as a slower
option, close to OpenRefine, but still slower than SPARQL. For the graph on the right, development
times are shown in hours, with OpenRefine estimated at 3 hours and the Wikidata API at 2 hours.
Based on the previous analysis, the OpenRefine tool is presented as an intermediate option between
the API and SPARQL (7 hours), and the Wikidata API as a more eficient option in aspects of software
development, being similar to the time of the standard API. This graph visualizes how the tools compare
in terms of performance and software development time, which can help you decide which is the best
tool to implement based on the needs at hand.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Conclusions and future work</title>
      <p>This analysis presents the importance of selecting an appropriate tool for the management of linked
open data, considering the capabilities and limitations of each of these, depending on the objectives and
available resources. As another option, it could be considered that the combination of the use of these
tools could benefit projects that involve the manipulation and analysis of data in Wikidata. Regarding
recommendations, the choice of the appropriate tool should be based on the specific needs of the project
and the level of technical experience of the work team that uses them. This study has demonstrated
significant diferences in performance and programming development time in terms of the use of the
tools. One of the points that was considered was the creation of graphs using linked open data, in
which SPARQL is the most eficient tool to create these graphs, although this presents a longer design
time. On the other hand, OpenRefine and the Wikidata API ofer an interesting combination in terms
of development speed and execution eficiency, making them eficient tools for projects with limited
resources. This work shows a detailed comparative analysis, to facilitate decision-making for the best
possible tool for the use of linked open data.</p>
      <p>As for future lines of research, it would be valuable to work on optimizing development time in
SPARQL to make it more accessible to users with less technical experience. In addition, the integration
of artificial intelligence could be investigated in order to improve aspects of the quality and treatment
of data linked to metadata.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>World</given-names>
            <surname>Wide Web Consortium</surname>
          </string-name>
          (
          <issue>W3C</issue>
          ),
          <year>W3c</year>
          ,
          <year>2024</year>
          . https://www.w3.org/.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>E.</given-names>
            <surname>Ávila</surname>
          </string-name>
          <string-name>
            <surname>Barrientos</surname>
          </string-name>
          ,
          <article-title>Linked data and its use in libraries, 2020</article-title>
          . http://ru.iibi.unam.mx/jspui/handle/ IIBI_UNAM/56.
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>World</given-names>
            <surname>Wide Web</surname>
          </string-name>
          <article-title>Consortium (W3C), Linked open data (lod</article-title>
          ),
          <year>2010</year>
          . https://www.w3.org/egov/ wiki/Linked_Open_Data.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>A. O.</given-names>
            <surname>Sierra</surname>
          </string-name>
          ,
          <article-title>Insertion of metadata from spanish libraries in wikidata: a linked open data model</article-title>
          ,
          <source>REVISTA ESPANOLA DE DOCUMENTACION CIENTIFICA 45</source>
          (
          <year>2022</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>B.</given-names>
            <surname>Hyland</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Atemezing</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Villazon-Terrazas</surname>
          </string-name>
          ,
          <article-title>Best practices for publishing linked data-</article-title>
          w3c working group note 09 january
          <year>2014</year>
          ,
          <year>2014</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>T.</given-names>
            <surname>Berners-Lee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Hendler</surname>
          </string-name>
          ,
          <string-name>
            <surname>O. Lassila,</surname>
          </string-name>
          <article-title>The semantic web: A new form of web content that is meaningful to computers will unleash a revolution of new possibilities</article-title>
          ,
          <year>2023</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>Wikimedia</given-names>
            <surname>Foundation</surname>
          </string-name>
          , Wikidata: Main page,
          <year>2023</year>
          . https://www.wikidata.org/wiki/Wikidata: Main_Page.
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>Wikimedia</given-names>
            <surname>Foundation</surname>
          </string-name>
          ,
          <article-title>Wikidata: Linked open data work-flow</article-title>
          ,
          <year>2021</year>
          . https://www.wikidata.org/ w/index.php?title=Wikidata:
          <article-title>Linked_open_data_work-flow&amp;oldid=1394378153.</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>F.</given-names>
            <surname>Erxleben</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Günther</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Krötzsch</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            <surname>Mendez</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Vrandečić</surname>
          </string-name>
          ,
          <article-title>Introducing wikidata to the linked data web</article-title>
          ,
          <source>in: The Semantic Web-ISWC 2014: 13th International Semantic Web Conference, Riva del Garda, Italy, October 19-23</source>
          ,
          <year>2014</year>
          .
          <source>Proceedings, Part I 13</source>
          , Springer,
          <year>2014</year>
          , pp.
          <fpage>50</fpage>
          -
          <lpage>65</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <given-names>D.</given-names>
            <surname>Vrandečić</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Krötzsch</surname>
          </string-name>
          ,
          <article-title>Wikidata: a free collaborative knowledgebase</article-title>
          ,
          <source>Communications of the ACM</source>
          <volume>57</volume>
          (
          <year>2014</year>
          )
          <fpage>78</fpage>
          -
          <lpage>85</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <given-names>I.</given-names>
            <surname>Nishanbaev</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Champion</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. A.</given-names>
            <surname>McMeekin</surname>
          </string-name>
          ,
          <article-title>A web gis-based integration of 3d digital models with linked open data for cultural heritage exploration</article-title>
          ,
          <source>ISPRS international journal of geo-information 10</source>
          (
          <year>2021</year>
          )
          <fpage>684</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <given-names>J.</given-names>
            <surname>Lehmann</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Isele</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Jakob</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Jentzsch</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Kontokostas</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P. N.</given-names>
            <surname>Mendes</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Hellmann</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Morsey</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Van Kleef</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Auer</surname>
          </string-name>
          , et al.,
          <article-title>Dbpedia-a large-scale, multilingual knowledge base extracted from wikipedia</article-title>
          ,
          <source>Semantic web 6</source>
          (
          <year>2015</year>
          )
          <fpage>167</fpage>
          -
          <lpage>195</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <given-names>A.</given-names>
            <surname>Chessa</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Fenu</surname>
          </string-name>
          ,
          <string-name>
            <given-names>E.</given-names>
            <surname>Motta</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Osborne</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D. R.</given-names>
            <surname>Recupero</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Salatino</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Secchi</surname>
          </string-name>
          ,
          <article-title>Data-driven methodology for knowledge graph generation within the tourism domain</article-title>
          , IEEE Access (
          <year>2023</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>M. B. Brandt</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          <string-name>
            <surname>Borsetti Gregorio Vidotti</surname>
            ,
            <given-names>J. E.</given-names>
          </string-name>
          <string-name>
            <surname>Santarem</surname>
            <given-names>Segundo</given-names>
          </string-name>
          ,
          <article-title>Legislative linked open data: a proposal of linked open data modelling for legislative information</article-title>
          ,
          <year>2018</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <given-names>D.</given-names>
            <surname>Diefenbach</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P. H.</given-names>
            <surname>Migliatti</surname>
          </string-name>
          ,
          <string-name>
            <given-names>O.</given-names>
            <surname>Qawasmeh</surname>
          </string-name>
          ,
          <string-name>
            <given-names>V.</given-names>
            <surname>Lully</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Singh</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Maret</surname>
          </string-name>
          ,
          <article-title>Qanswer: A question answering prototype bridging the gap between a considerable part of the lod cloud and end-users</article-title>
          ,
          <source>in: The World Wide Web Conference</source>
          ,
          <year>2019</year>
          , pp.
          <fpage>3507</fpage>
          -
          <lpage>3510</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <given-names>A.</given-names>
            <surname>Uzun</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Uzun</surname>
          </string-name>
          ,
          <article-title>Semantic enrichment of mobile and wifi network data, Semantic Modeling and Enrichment of Mobile and WiFi Network Data (</article-title>
          <year>2019</year>
          )
          <fpage>59</fpage>
          -
          <lpage>96</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <given-names>M.</given-names>
            <surname>Martinez</surname>
          </string-name>
          ,
          <article-title>Quality metrics to validate government public open data sets</article-title>
          ,
          <year>2022</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <given-names>K.</given-names>
            <surname>Thornton</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Seals-Nutt</surname>
          </string-name>
          ,
          <string-name>
            <surname>M. Van Remoortel</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. M.</given-names>
            <surname>Birkholz</surname>
          </string-name>
          , P. De Potter,
          <article-title>Linking women editors of periodicals to the wikidata knowledge graph</article-title>
          ,
          <source>Semantic Web</source>
          <volume>14</volume>
          (
          <year>2023</year>
          )
          <fpage>443</fpage>
          -
          <lpage>455</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <given-names>H.</given-names>
            <surname>Chalupsky</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Szekely</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Ilievski</surname>
          </string-name>
          ,
          <string-name>
            <given-names>D.</given-names>
            <surname>Garijo</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            <surname>Shenoy</surname>
          </string-name>
          ,
          <article-title>Creating and querying personalized versions of wikidata on a laptop</article-title>
          ,
          <source>arXiv preprint arXiv:2108.07119</source>
          (
          <year>2021</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <given-names>S. L.</given-names>
            <surname>Freshour</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Kiwala</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K. C.</given-names>
            <surname>Cotto</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A. C.</given-names>
            <surname>Cofman</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. F.</given-names>
            <surname>McMichael</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J. J.</given-names>
            <surname>Song</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Grifith</surname>
          </string-name>
          ,
          <string-name>
            <given-names>O. L.</given-names>
            <surname>Grifith</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A. H.</given-names>
            <surname>Wagner</surname>
          </string-name>
          ,
          <article-title>Integration of the drug-gene interaction database (dgidb 4.0) with open crowdsource eforts</article-title>
          ,
          <source>Nucleic acids research</source>
          <volume>49</volume>
          (
          <year>2021</year>
          )
          <fpage>D1144</fpage>
          -
          <lpage>D1151</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          [21]
          <string-name>
            <surname>A. M. F. García</surname>
            ,
            <given-names>M. I. M.</given-names>
          </string-name>
          <string-name>
            <surname>García</surname>
            ,
            <given-names>R. B.</given-names>
          </string-name>
          <string-name>
            <surname>Gallinas</surname>
          </string-name>
          ,
          <string-name>
            <surname>M. M. Sánchez</surname>
            ,
            <given-names>M. E. B.</given-names>
          </string-name>
          <string-name>
            <surname>Gutiérrez</surname>
          </string-name>
          ,
          <article-title>Integration and open access system based on semantic technologies: A use case</article-title>
          applied to university research facet,
          <source>International Journal on Semantic Web and Information Systems (IJSWIS) 18</source>
          (
          <year>2022</year>
          )
          <fpage>1</fpage>
          -
          <lpage>19</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          [22]
          <string-name>
            <given-names>A.</given-names>
            <surname>Vinoth</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            <surname>Thangasamy</surname>
          </string-name>
          ,
          <string-name>
            <given-names>R.</given-names>
            <surname>Nithya</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            <surname>Subalalitha</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Mahendhiran</surname>
          </string-name>
          ,
          <article-title>The impact of tamil python programming in wikisource</article-title>
          ,
          <source>in: International Conference on Speech and Language Technologies for Low-resource Languages</source>
          , Springer,
          <year>2023</year>
          , pp.
          <fpage>79</fpage>
          -
          <lpage>90</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          [23]
          <string-name>
            <given-names>S.</given-names>
            <surname>Deng</surname>
          </string-name>
          ,
          <string-name>
            <given-names>G.</given-names>
            <surname>Heng</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            <surname>Xu</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Zhu</surname>
          </string-name>
          ,
          <string-name>
            <given-names>X.</given-names>
            <surname>Li</surname>
          </string-name>
          ,
          <article-title>Enhance the discovery and interoperability of culturally rich information: the chinese women poets wikiproject</article-title>
          ,
          <year>2022</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          [24]
          <string-name>
            <given-names>S. C.</given-names>
            <surname>Schmidt</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            <surname>Thiery</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Trognitz</surname>
          </string-name>
          ,
          <article-title>Practices of linked open data in archaeology and their realisation in wikidata</article-title>
          ,
          <source>Digital</source>
          <volume>2</volume>
          (
          <year>2022</year>
          )
          <fpage>333</fpage>
          -
          <lpage>364</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          [25]
          <string-name>
            <given-names>L.</given-names>
            <surname>Álvarez-Azcárraga</surname>
          </string-name>
          ,
          <article-title>Radical openness and free knowledge: Repository of open-access mexican academic journals through wikidata, Revista científica (</article-title>
          <year>2023</year>
          )
          <fpage>27</fpage>
          -
          <lpage>39</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          [26]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:rest api,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata:REST_API.
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          [27]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:stable interface policy,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata:Stable_ Interface_Policy.
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          [28]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:sparql query service/queries,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata: SPARQL_query_service/queries.
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          [29]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:sparql query service/help,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata: SPARQL_query_service/Wikidata_Query_Help/es.
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          [30]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:sparql tutorial,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata:SPARQL_ tutorial/es.
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          [31]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          ,
          <source>Wikidata:pywikibot - python 3 tutorial</source>
          ,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata: Pywikibot_-_
          <string-name>
            <surname>Python</surname>
          </string-name>
          _3_Tutorial.
        </mixed-citation>
      </ref>
      <ref id="ref32">
        <mixed-citation>
          [32]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Manual:pywikibot/wikidata,
          <year>2024</year>
          . https://www.mediawiki.org/wiki/Manual:Pywikibot/ Wikidata.
        </mixed-citation>
      </ref>
      <ref id="ref33">
        <mixed-citation>
          [33]
          <string-name>
            <surname>Wikidata</surname>
          </string-name>
          , Wikidata:tools/openrefine/editing,
          <year>2024</year>
          . https://www.wikidata.org/wiki/Wikidata: Tools/OpenRefine/Editing.
        </mixed-citation>
      </ref>
      <ref id="ref34">
        <mixed-citation>
          [34]
          <string-name>
            <surname>OpenRefine</surname>
          </string-name>
          , Overview of wikibase support,
          <year>2024</year>
          . https://openrefine.org/docs/manual/wikibase/ overview.
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>