In this poster paper we provide an overview of the OpenCitations Project (http://opencitations.net) and of its main outcome, the OpenCitations Corpus, which is an open repository of scholarly citation data made available under a CC0 license, providing in RDF accurate citation information harvested from the scholarly literature, starting from the PubMed Central OA subset. RASH: https://w3id.org/oc/paper/occ-poster-iswc2016.html This is the main premise behind the OpenCitations Project and a number of other complementary initiatives including Semantic Lancet3 [2], Springer LOD4, OpenAIRE5 [1] and Scholarly Data6 [3]. Since the beginning of July, OpenCitations has started to ingest and process the reference lists of scholarly papers available in Europe PubMed Central7. In this paper we provide a brief overview of its main components that make the extraction and description of such reference lists in RDF possible.
Reference lists from academic articles are the core elements of scholarly
communication, since they both permit the attribution of credit and integrate our
independent research endeavours. But the cruel reality is that they are not freely
available. For instance, UK research universities each pay tens of thousands of
pounds annually [
Citation data now needs to be recognized as a part of the Commons – those works that are freely and legally available for sharing – and placed in an open repository, where they should be stored in appropriate machine-readable formats so as to be easily reused by machines to assist people in producing novel services.
The OpenCitations Project (http://opencitations.net) is creating an open
dataset of citation data integrated with a SPARQL endpoint8 and a very simple
Web interface that shows only the data about bibliographic entities9. Its main
output is the Open Citations Corpus (OCC), an open repository of scholarly
citation data made available under a Creative Commons CC0 license10, which
provides accurate bibliographic references harvested from the scholarly literature,
described using the SPAR Ontologies11 [
The OCC stores metadata relevant to these citations in RDF, encoded as JSON-LD, and makes them available through a SPARQL endpoint (and, in the near future, as downloadable datasets). It includes information about six diferent kinds of bibliographic entity: – bibliographic resources (br) – resources that cite/are cited by other bibliographic resources (e.g. journal articles), or that contain such citing/cited resources (e.g. journals); – resource embodiments (re) – details of the physical or digital forms in which the bibliographic resources are made available by their publishers; – bibliographic entries (be) – the literal textual bibliographic entries occurring in the reference lists within bibliographic resources, that reference other bibliographic resources; – responsible agents (ra) – names of agents having certain roles with respect to bibliographic resources (i.e. names of authors, editors, publishers, etc.); – agent roles (ar) – roles held by agents with respect to bibliographic resources (e.g. author, editor, publisher); – identifiers (id) – external identifiers (e.g. DOI, ORCID, PubMedID) associated with the bibliographic entities.
The corpus URL (https://w3id.org/oc/corpus/) identifies the entire OCC, which is composed of several sub-datasets, one for each of the aforementioned bibliographic entities included in the corpus. Each of these has a URL composed by sufixing the corpus URL with the two-letter short name for the class of entity (e.g. “be” for a bibliographic entry) followed by an oblique slash (e.g. https://w3id.org/oc/corpus/be/). Each dataset is described appropriately by means of the Data Catalog Vocabulary12 and the VoID Vocabulary13.
Upon initial curation into the OCC, a URL is assigned to each entity within
each sub-dataset, all of which can be accessed in diferent formats (HTML,
RDF/XML, Turtle, and JSON-LD) via content negotiation. Each entity URL is
composed by sufixing the sub-dataset URL with a number assigned to each
resource, unique among resources of the same type, which increments for each new
8 https://w3id.org/oc/sparql
9 Additional and more user-friendly interfaces will be available in the coming months,
and will be described in the project homepage.
10 https://creativecommons.org/publicdomain/zero/1.0/legalcode
11 http://www.sparontologies.net/
12 https://www.w3.org/TR/vocab-dcat/
13 https://www.w3.org/TR/void/
Jailbreaking your reference lists
entry in that resource class. For instance, the resource https://w3id.org/oc/
corpus/be/537 is the 537th bibliographic entry recorded within the OCC. Each
of these entities has associated metadata describing its provenance by means of
PROV-O14 and its PROV-DC extension15 (e.g. https://w3id.org/oc/corpus/
be/537/prov/se/1). In particular, we keep track of the curatorial activities
related to each OCC entity, the curatorial agents involved, and their roles.
Additional information about OCC’s handling of citation the data, and the way they
are represented in RDF, are detailed in the oficial OCC Metadata Document
[
We are currently working on two diferent aspects. First of all, we are developing tools for linking the resources within the OCC with those included in other datasets, e.g. Scholarly Data. In addition, we are experimenting with the use of multiple parallel instantiations of SPACIN, so as to increase the amount of new information that can be processed daily.