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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Augmenting Digital Textbooks with Reusable Smart Learning Content: Solutions and Challenges⋆</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>University of Pittsburgh</institution>
          ,
          <addr-line>Pittsburgh PA 15260</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>1902</year>
      </pub-date>
      <abstract>
        <p>A powerful set of educational tools has emerged over the last decade with the rise in the adoption of online adaptive learning content. An increasingly popular tool in this space is the “intelligent textbook” as a platform to support and distribute content for e-learning, given its resemblance with real-life physical books. Existing eforts in this direction include the development of digital textbooks where both textual content and interactive learning activities (i.e., examples, problems, etc.) are carefully handcrafted by the authors so that they are perfectly placed to follow the knowledge acquisition-practice flow. However, this approach is very time-consuming, and it requires the work of high-expertise authors. In this work, we suggest and discuss a scalable solution: we take existing digital textbooks and augment them by using repositories of existing online learning material associated with the subject matter. We present our current work in this direction and discuss challenges and opportunities for the future work.</p>
      </abstract>
      <kwd-group>
        <kwd>Smart Learning Content</kwd>
        <kwd>Intelligent Textbooks</kwd>
        <kwd>Educational Recommendations</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>A gradual switch from paper-based to “electronic” textbooks (e-textbooks) opened
an exciting opportunity to extend these classic learning tools with
functionalities not previously available in paper format. Among the most appealing and
popular ways to extend textbooks with new functionalities is converting
examples and problems, a traditional component of textbooks in many domains, into
interactive learning activities. This approach makes textbooks truly interactive
and augments learning by reading with learning by doing.</p>
      <p>One of the first domains to embrace this kind of interactive textbook was
computer science education (CSE) where the development of interactive learning
activities from algorithm animations to automatically-assessed programming
problems was a popular research direction. The need to integrate interactive learning
⋆ Copyright © 2022 for this paper by its authors. Use permitted under Creative</p>
      <p>
        Commons License Attribution 4.0 International (CC BY 4.0).
activities with online textbooks has been extensively discussed by the computer
science education community for many years [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] and some best examples of
interactive textbooks have been produced for computer science subjects. Among
these examples are ELM-ART [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], the first adaptive textbook with interactive
problems and examples for learning LISP, OpenDSA [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ], the first open-source
infrastructure for collaborative construction of e-textbooks with interactive
animations and problems (originally developed for Data Structures and Algorithms
course), and RuneStone books [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ] a popular infrastructure for presenting
online textbooks for programming augmented with interactive learning activities.
These and other interactive textbooks have been extensively evaluated in various
learning contexts and their efectiveness was convincingly demonstrated [
        <xref ref-type="bibr" rid="ref11 ref21 ref31">31, 11,
21</xref>
        ].
      </p>
      <p>However, the current platforms for the development and delivery of
interactive textbooks for CSE share the same problem: the “custom” nature of their
production. These textbooks are expected to be developed “as a whole” for a
specific purpose, with text and interactive problems developed and integrated
together as a part of the authoring process. This approach allows developing
excellent examples of interactive textbooks but doesn’t support scaling up this
process. For each “holistically developed” interactive textbook, there are dozens
of professionally authored textbooks on the same subject that are not augmented
with interactive content because this option has not been considered at the time
of their creation. At the same, there are large repositories of interactive learning
content of diferent types that could be used to augment these books. A missing
piece in the infrastructure is the integration of an arbitrary textbook with its
corresponding interactive content.</p>
      <p>
        An important step towards building this infrastructure was done in OpenDSA
project [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ], which ofered an opportunity to connect any LTI-compatible
interactive content to OpenDSA textbooks. However, it is still focused on custom-built
textbooks and doesn’t support existing textbook. The project presented in this
paper attempts to take the next step in this direction and make both textbooks
and integrative learning content reusable. Our goal is to build an infrastructure
that allows turning any textbook available in electronic format (such as PDF)
into an interactive textbook by augmenting it with interactive learning
content from existing repositories. This paper presents an important component of
this infrastructure - and interface that support augmentation of existing books
with interactive content without breaking the structure of these textbooks. In
the following sections, we present our current implementation of this interface,
demonstrate the approach for integrating smart content into textbook structure,
and discuss future work in this direction.
2
      </p>
    </sec>
    <sec id="sec-2">
      <title>Related Work</title>
      <p>
        Multiple research eforts have been carried out during the last decade in order
to develop technology-enhanced textbooks. Electronic Textbooks (e-textbooks)
support content distribution at scale in diferent formats and for diferent
purposes. In recent years, there have been many discussions that project what
technological enhancements could surround the use of intelligent e-textbooks in
education [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]. Among these discussions, a few noteworthy contributions such as the
use of intelligent question-asking [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ], intelligent tutoring [
        <xref ref-type="bibr" rid="ref29">29</xref>
        ], and
augmentation of assessment questions [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] bring to the light the possibilities of interesting
enhancements in smart digital textbooks. On the one hand, these technological
enhancements could be implemented as artificially intelligent agents or systems
in e-textbooks that deliver, recommend or scafold the learner’s needs while
reading [
        <xref ref-type="bibr" rid="ref32">32</xref>
        ]. On the other hand, it could be possible to integrate reusable smart
content that are adaptive to the needs of the user, without necessarily adapting
or personalizing the system behaviour to the learner. In general, the main idea
has been to maintain the afordances of physical textbooks combined with the
capabilities of web pages. However, some eforts have been made to
incorporate the design of the novel functionalities for students that could expand the
potentialities of intelligent textbooks [
        <xref ref-type="bibr" rid="ref30">30</xref>
        ].
      </p>
      <p>
        In our work, we take this second route of augmentation of intelligent
textbooks with adaptive, personalized learning material presented as Smart Learning
Content (SLC) [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. Typically, there are 5 diferent levels of SLCs [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], namely,
1. Level 1 SLCs are independent of the delivery platform for learning. In this
setup, the variables used by the SLC to personalize content do not persist,
once the session is closed and is stateless.
2. Level 2 The SLC and the delivery platform for learning are integrated into
a single system and the delivery platform saves the data produced by the
SLC, which is used across several user sessions. A limitation of this setup is
that the SLC would need to be developed specifically for the delivery
platform and cannot exist outside of the system. For example, CodeAcademy 1,
KhanAcademy 2, Brilliant 3
3. Level 3 All content in the SLCs is internal to the platform, but the delivery
platform supports multiple SLCs. For example, OpenDSA [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]
4. Level 4 The platform supports multiple SLCs and allows the use of external
content, using proprietary protocols to retrieve the external content. For
example, BlueJ or Moodle with plug-in support, TestMyCode [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ], A+ [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]
and JavaGuide [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ].
5. Level 5 The platform supports multiple SLCs that use standard protocols,
such as Learning Tools Interoperability (LTI), allowing for maximum
flexibility. For example, LTI with Moodle 4.
      </p>
      <p>
        Among these levels, our earlier discussions cover implementations that could
be considered as level 2 SLCs [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. We also discussed implementations that utilize
the benefits of Learning Tools Interoperability (LTI) [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] to integrate early
implementations of level 5 SLCs in the intelligent textbooks. In this work, we explore
      </p>
      <sec id="sec-2-1">
        <title>1 http://codeacademy.com</title>
      </sec>
      <sec id="sec-2-2">
        <title>2 https://khanacademy.org</title>
      </sec>
      <sec id="sec-2-3">
        <title>3 https://brilliant.org</title>
      </sec>
      <sec id="sec-2-4">
        <title>4 https://docs.moodle.org/400/en/LTI_and_Moodle</title>
        <p>possibilities for an implementation that could meet the gold standards discussed
as levels 3 and 4 in our prior work, that is, to support multiple SLCs that are
both native and external resource recommendations to the delivery platform. In
this case, we set the platform content delivery to be the intelligent textbook.
3</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Reading System to Support Social Aspects of Learning</title>
      <p>
        For our implementation in this work, we utilize our reading system [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], a
platform for social navigation and social aspects of learning. This system ofers
many features for the students in a course such as textual annotations and
social comparison plots (for comparing self-progress with the progress of the rest
of the class peers). The system is intended to support and enhance self-regulated
learning in the student using this to read e-textbooks. The system distributes
course content by leveraging the use of open and accessible textbook materials
on topics in various courses ranging from Introductory Information Retrieval to
Introductory Object-Oriented Programming. It provides helpful visualizations
to view the reading progress over the duration of the course, with interactive
multiple-choice quizzes at the end of each section, presented within a pop-up
window. Considering these aspects, this system provides an excellent platform
to support extensible SLCs like animated programming exercises [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ],
programming construction examples [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] and external content recommendations (e.g.,
Wikipedia articles) [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ]. By default, there are native content recommendations
available in an intelligent textbooks system, which could be considered to satisfy
the principles of level 3 SLCs.
4
      </p>
    </sec>
    <sec id="sec-4">
      <title>Augmenting Reusable Smart Learning Content</title>
      <p>We set the goals for level 3 and 4 SLCs, which we describe again here,
1. Level 3 Integrate Multiple SLCs that are native to the platform such as</p>
      <p>
        OpenDSA [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]
2. Level 4 Support multiple SLCs on the platform such that external content
can be integrated into the system.
      </p>
      <p>Currently, we implemented two ways to integrate SLC into a textbook: a
list of recommended videos (see the red tab in Fig. 1) and a list of statically
attached interactive exercises (see the green tab in Fig. 1). The video interface
was developed for an information retrieval textbook. It shows recommended
videos using thumbnails, which work as links to related content on YouTube5 and
multimedia sharing websites. These implementations could consider a ranking
and rating-based approach to listing the content to allow the factor of
“human-inthe-loop” recommendations to support and enhance intelligent recommendations
to the users of these systems and their students in these courses.</p>
      <sec id="sec-4-1">
        <title>5 https://www.youtube.com</title>
        <p>The second way (a list of interactive programming exercises) was developed
for e-textbooks on introductory programming. The list of available exercise types
with descriptions is provided in Table 1. These exercises range from simple
problems that test the student’s understanding of the inputs or outputs of a given
program to puzzles that can be solved in several steps. Interactive and animated
examples could make the process of reading and understanding the code more
engaging for the reader. This could scafold a student’s learning in their process
of understanding a course on introductory concepts in programming. Such an
SLC integration could possibly turn the mundane process of reading a textbook
into a rich, interactive experience that ofers possibilities for hands-on content
experimentation. Further, students who are curious learners can explore the
concepts discussed on a page with a related live, interactive examples to keep them
engaged.</p>
        <p>System</p>
        <p>Types of Exercises
We collected a set of SLCs from various sources, in order, to ofer a wide range
of online learning activities to students. The available content ranges from a low
level of interactivity (i.e., educational videos and worked-out examples) to more
interactive activities (i.e., parsons problems and coding-from-scratch problems).
In this paper, we will focus on two courses as study cases:
1. A Graduate course on Information Retrieval based on an open source
textbook
2. An Undergraduate course on Programming in Python with the main
textbook for reference, “Python for Everybody” 6.
5.1</p>
        <sec id="sec-4-1-1">
          <title>An Information Retrieval Textbook with Smart Content</title>
          <p>For the Information Retrieval course we focused on augmenting the existing
reading resources within the system with educational videos scraped from the
web, more specifically from the YouTube platform 7. We decided to present this
augmentation as non-intrusive recommendations shown at the right margin of
the active page. The steps we followed for generating these educational video
recommendations are presented below:
1. Candidate videos’ collection : Collecting a set of videos from YouTube
covering the core Information Retrieval concepts presented in the course. We
determined this set of concepts by automatically extracting them from the
textual content of the course reading sections by following one of the approaches</p>
        </sec>
      </sec>
      <sec id="sec-4-2">
        <title>6 https://www.py4e.com 7 https://www.youtube.com/results?search_query=information+retrieval</title>
        <p>
          for presented by Thaker et.al. in [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ]. In this concept extraction approach,
ifrst noun phrase chunking is performed to obtain candidate keyphrases from
a text and then the keyphrases are ranked based on their tf-idf score 8. As an
outcome of this process, each section of the course ends up associated with
a list of concepts, which are covered in the corresponding text. With this
list of concepts (mainly unigrams and bigrams) we prepared a set of queries
in the format “information retrieval concept” (e.g. “information retrieval zipf
law”). We executed the queries by using the YouTube Search API, and for
each query that is executed, we considered only the top 20 videos as potential
candidates.
2. Videos’ textual representation : We proceeded to get the transcripts of the
candidate videos by using the youtube-dl API9, so we could get the content
presented in a textual format. Additionally, we concatenated the title and
the description of the video (which was useful for having a representation
for videos without an available transcript).
3. Videos’ concept extraction and initial relevancy filter : Next step was
extracting the keyphrases from the textual representation of the video, which we
consider as a proxy for identifying the concepts covered there. For that task
we simply looked for exact textual match between the textual transcripts
and the list of concepts of the corresponding section. Thus, for each video
we ended up with a list of concepts (keyphrases) representing the covered
content. As an initial filter of video relevancy, we calculated the proportion
of concepts covered by the video and the set of concepts of each section. If
the match of the concepts presented in the video and the section was over
5%, we considered the video as “initially relevant”.
4. Reading-Video Similarity Calculation : We computed the similarity between
the initially relevant videos and the reading section by using diferent text
similarity metrics like Cosine and Jaccard similarity and applying tf-idf as
pre-processing of the textual data.
5. Video Recommendations’ Presentation : Finally, we sort the videos
descending by the similarity score calculated in the previous step and show only
the top 20 on the tab (see Fig. 2). We display the video title along with its
thumbnail, which, when clicked, plays a video within a pop-up window (see
Fig. 3)
        </p>
        <p>As a result, while navigating the reading sections through the online reader
students have also the option of deepening their acquired knowledge through
the recommended videos list. These external materials present the same or part
content from a diferent perspective or at a diferent level of detail. Finally,
in order to get feedback from the students about the suitability of the
recommended material for the section that they are reading, we added a section within
the video watching for them to express their opinion about the quality of the
recommendation (see the top right section in Fig. 3).</p>
      </sec>
      <sec id="sec-4-3">
        <title>8 https://github.com/khushsi/ConceptExtractor</title>
      </sec>
      <sec id="sec-4-4">
        <title>9 https://youtube-dl.org/</title>
        <sec id="sec-4-4-1">
          <title>A Python Programming Textbook with Smart Content</title>
          <p>To support a Python Programming course we augmented a popular textbook
“Python for Everybody” with smart content. This textbook is available in several
formats, including as a PDF10. It consists of several chapters that cover the basics
of Python programming. The textbook starts with delivering the course content
from scratch, going into sequential topics, and keeping the target audience as
novice or beginner-level programmers in Python. We use this setup to experiment
with SLC implementations to help practise programming in Python with a set of
worked out examples and programming problems. We target SLCs that cannot
be directly covered within the text. We think that the programming exercises
could be presented as a list of short problems related to the material being read
in a given page, section or chapter of the book.</p>
          <p>
            To test our current infrastructure, we attached a range of smart learning
content for Python to various sections of the textbook as shown in Fig. 4. When
a link to an SLC item from the list of entries for smart content is clicked, it
launches a dialog instance with the specific programming example or problem.
For example, Fig. 5 shows a code tracing problem from QuizPET system (Quizzes
for Python Educational Testing) [
            <xref ref-type="bibr" rid="ref6">6</xref>
            ]. Another kind of programming exercises for
Python that we made available in the book are interactive worked examples of
program construction from PCEX system with step-wise program explanations
and walk-through (Fig. 6. These exercises allow for the student to focus on
specifics of a given program).
          </p>
          <p>
            In total, we demonstrated the ability to connect six types of SLC worked
examples and problems listed in Table 1. A more detailed description of these
SLC types could be found in [
            <xref ref-type="bibr" rid="ref14">14</xref>
            ]. When augmenting the book with SLC, we
considered Python programming activities that are related to the topics covered
in the text of a particular page of section in a chapter. These programming
activities use the knowledge or concepts covered in the textbook up to that
point and avoid the concepts that will be covered later in the textbook.
          </p>
          <p>
            In the future version, we hope to provide a smart textbook authoring system
for course instructors, which will allow them to augment the same textbook with
SLC that they want to use in their classes. A prototype of this authoring system
with learning analytics support can be found in [
            <xref ref-type="bibr" rid="ref1">1</xref>
            ]. We also plan to support the
authoring process with instructor-focused content recommender system [
            <xref ref-type="bibr" rid="ref9">9</xref>
            ]. This
could be considered as our long term goal for smart content, but in the current
work of smart content design for programming exercises, we only focus on the
interface for delivering SLC to students through a textbook.
6
          </p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Discussion and Future Work</title>
      <p>
        With our implementation, we show that it is possible to integrate and augment
e-textbooks with multiple SLCs. They are available as non-intrusive sidebars
for the reader to explore material relevant, without losing focus on the main
10 https://www.py4e.com/book
text content of the intelligent textbook. Dynamic SLC recommendations
provided at diferent levels of granularity by relevance (given section, chapter, page
or paragraph) is our next step to explore. Determining the most appropriate
granularity and dificulty level of the programming exercises in the smart
content to act as useful recommendations that scafold students’ learning. Further,
adaptations could model the patterns of user or student interactions with the
system to fine-tune the recommended SLC, further governed by the reader’s
control on the (“human-in-the-loop”) curation of the SLCs listed with rating and
ranking features. SLC of other types could take no inputs from the user, but
present as passive recommendations in relation to the concepts covered at a
page or section. Learner-sourced approaches to recommend questions [
        <xref ref-type="bibr" rid="ref16 ref20">20, 16</xref>
        ] is
another interesting research opportunity to explore and address the challenge of
dynamic content allocation. Questions that are most relevant to a page, section
or chapter could be dynamically curated in the side panel. The learner-sourced
SLC could be generated by peers taking the course or students who took the
course. This material could be rated and ranked by the current users to improve
the recommendations provided. Reusing resources in this manner could
potentially open the doors to exemplary SLCs integrated into intelligent textbooks
for other learner content delivery systems. These opportunities can be realized
by overcoming a few challenges discussed below.
6.1
      </p>
      <sec id="sec-5-1">
        <title>Challenges</title>
        <p>
          In our implementation towards integrating multiple SLCs, we find that
allocating the right content could be a potential challenge. While it is possible to
support personalized, integrable and adaptive SLCs for specific chapters or
sections within intelligent textbooks on diferent topics, it is a challenge to make
it scale up to diferent topics and courses in these system implementations.
Another challenge is that for instructors teaching these programming courses, as
discussed by Chau et. al. [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ], the content allocation for all the intended concepts
in the course may not be possible and this makes this implementation potentially
static. Further, a scope for future exploration is the allocations that adapts to the
teachers’ understanding of the course topics [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ] is another challenge. It would
especially be interesting to include a smart content that is modeled by the topic
and the knowledge levels of the course instructors. Hence, the presented content
would then augment their understanding of the topics covered in the course. All
these three challenges consider a “human-in-the-loop” implementation. A final
challenge is to integrate an SLC to augment the content presented in the
digital textbook as a recommender system that involves less human intervention to
improve its personalization. An example to support such an integration would
be recommendations to external web resources like Wikipedia with additional
information is not native to the content available within the text, but augments
the information provided without much scope for the user to rate or rank these
recommendations to match their personal choices. An implementation in this
direction [
          <xref ref-type="bibr" rid="ref22">22</xref>
          ] sets possible paths for us to explore as augmented SLC in our future
work and as a means to overcome this challenge. In the light of understanding
and overcoming these challenges, we will be able to explore and support more
types of dynamic SLCs in our future iterations of intelligent textbooks.
7
        </p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>Conclusions</title>
      <p>In this work, we present an interesting perspective on integrating smart learning
content (SLCs) in intelligent textbooks as the delivery platform. Along with
the possibility of supporting multiple SLCs, they could be native and external
resources using open, proprietary protocols (levels 3 and 4 SLCs) for retrieval.
This meets our goal that we set forth of building an infrastructure that could turn
any ordinary e-textbook into an intelligent, adaptive and interactive textbook.
Although not our goal to begin with, since our implementation uses the resources
that are not native, but external to the intelligent textbooks framework (we
benefit from using the SLC repositories developed by others), we present a system
that is flexible, suggesting that the learning content delivery platform can be
interchangeable (level 5). The seamless integration of the SLCs into intelligent
textbooks, allows for the possibility of interactive and engaging learning content
delivery platforms for curious learners. In the long term, this allows for better
adoption of enhanced intelligent e-textbooks. Finally, we discuss the challenges
encountered while making scalable integration of SLCs into the deliver platform.
We discuss existing solutions that could allow us to overcome these challenges.
Technical advancements in the not so distant future could help address these
challenges with eficient protocols for seamless augmentation of smart learning
content without breaking the structure of the e-textbooks.
Acknowledgements We acknowledge the help ofered by our colleagues in the
implementation of parser and smart learning content allocation in our intelligent
textbook implementation. Also, the work of one of the authors was funded by
CONICYT PFCHA/ Doctorado Becas Chile/ 2018 - 72190680.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Albó</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hernández-Leo</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>Knowledge-based design analytics for authoring courses with smart learning content</article-title>
          .
          <source>International Journal of Artificial Intelligence in Education 32</source>
          ,
          <fpage>4</fpage>
          -
          <lpage>27</lpage>
          (
          <year>2022</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Akhuseyinoglu</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Learning content integration into an electronic textbook for introductory programming (</article-title>
          <year>2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>He</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          : Reading mirror:
          <article-title>Social navigation and social comparison for electronic textbooks</article-title>
          .
          <source>In: iTextbooks@AIED</source>
          (
          <year>2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Webex: Learning from examples in a programming course</article-title>
          .
          <source>In: WebNet</source>
          (
          <year>2001</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Edwards</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kumar</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Malmi</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Benotti</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Buck</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ihantola</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Prince</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sirkiä</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Urquiza</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vihavainen</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wollowski</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Increasing adoption of smart learning content for computer science education</article-title>
          .
          <source>In: Proceedings of the Working Group Reports of the 2014 on Innovation amp; Technology in Computer Science Education Conference</source>
          . p.
          <fpage>31</fpage>
          -
          <lpage>57</lpage>
          . ITiCSEWGR '14,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery, New York, NY, USA (
          <year>2014</year>
          ). https://doi.org/10.1145/2713609.2713611
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Malmi</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hosseini</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Guerra</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sirkiä</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pollari-Malmi</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          :
          <article-title>An integrated practice system for learning programming in python: design and evaluation</article-title>
          .
          <source>Research and Practice in Technology Enhanced Learning</source>
          <volume>13</volume>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schwarz</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Weber</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          :
          <article-title>Electronic textbooks on WWW: from static hypertext to interactivity and adaptivity</article-title>
          , pp.
          <fpage>255</fpage>
          -
          <lpage>261</lpage>
          . Educational Technology Publications, Englewood Clifs, New Jersey (
          <year>1997</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Chacon</surname>
            ,
            <given-names>I.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Akhuseyinoglu</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Integrating textbooks with smart interactive content for learning programming</article-title>
          .
          <source>In: iTextbooks@AIED</source>
          (
          <year>2021</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Chau</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Learning content recommender system for instructors of programming courses</article-title>
          .
          <source>In: AIED</source>
          (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Dresscher</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chacon</surname>
            ,
            <given-names>I.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.A.</given-names>
          </string-name>
          :
          <article-title>Generation of assessment questions from textbooks enriched with knowledge models</article-title>
          .
          <source>In: iTextbooks@AIED</source>
          (
          <year>2021</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Ericson</surname>
            ,
            <given-names>B.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Guzdial</surname>
            ,
            <given-names>M.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Morrison</surname>
            ,
            <given-names>B.B.</given-names>
          </string-name>
          :
          <article-title>Analysis of interactive features designed to enhance learning in an ebook</article-title>
          .
          <source>In: Proceedings of the 11th International Conference on International Computing Education Research</source>
          . ACM (aug
          <year>2015</year>
          ). https://doi.org/10.1145/2787622.2787731,
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Ericson</surname>
            ,
            <given-names>B.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Miller</surname>
            ,
            <given-names>B.N.</given-names>
          </string-name>
          :
          <article-title>Runestone: A platform for free, on-line, and interactive ebooks</article-title>
          .
          <source>In: Proceedings of the 51st ACM Technical Symposium on Computer Science Education</source>
          . p.
          <fpage>1012</fpage>
          -
          <lpage>1018</lpage>
          . Association for Computing Machinery, New York, NY, USA (
          <year>2020</year>
          ), https://doi.org/10.1145/3328778.3366950
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Fouh</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Karavirta</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Breakiron</surname>
            ,
            <given-names>D.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hamouda</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hall</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Naps</surname>
            ,
            <given-names>T.L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shafer</surname>
            ,
            <given-names>C.A.</given-names>
          </string-name>
          :
          <article-title>Design and architecture of an interactive etextbook - the OpenDSA system</article-title>
          .
          <source>Science of Computer Programming</source>
          <volume>88</volume>
          ,
          <fpage>22</fpage>
          -
          <lpage>40</lpage>
          (
          <year>2014</year>
          ). https://doi.org/https://doi.org/10.1016/j.scico.
          <year>2013</year>
          .
          <volume>11</volume>
          .040
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Hosseini</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Akhuseyinoglu</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Malmi</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pollari-Malmi</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schunn</surname>
            ,
            <given-names>C.D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sirkiä</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          :
          <article-title>Improving engagement in program construction examples for learning python programming</article-title>
          .
          <source>International Journal of Artificial Intelligence in Education</source>
          <volume>30</volume>
          ,
          <fpage>299</fpage>
          -
          <lpage>336</lpage>
          (
          <year>2020</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Hsiao</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Guiding students to the right questions: adaptive navigation support in an e-learning system for java programming</article-title>
          .
          <source>J. Comput. Assist. Learn</source>
          .
          <volume>26</volume>
          ,
          <fpage>270</fpage>
          -
          <lpage>283</lpage>
          (
          <year>2010</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16.
          <string-name>
            <surname>Huang</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hancock</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Clemson</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Yeo</surname>
            ,
            <given-names>G.C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Harney</surname>
            ,
            <given-names>D.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Denny</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Denyer</surname>
          </string-name>
          , G.:
          <article-title>Selecting student-authored questions for summative assessments</article-title>
          .
          <source>bioRxiv</source>
          (
          <year>2020</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <surname>Ihantola</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Karavirta</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          :
          <article-title>Two-dimensional parson's puzzles: The concept, tools, and first observations</article-title>
          .
          <source>Journal of Information Technology Education</source>
          <volume>10</volume>
          ,
          <fpage>119</fpage>
          -
          <lpage>132</lpage>
          (
          <year>2011</year>
          ), https://jite.org/documents/Vol10/JITEv10IIPp119-132Ihantola944.pdf
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <surname>Karavirta</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ihantola</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Koskinen</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          :
          <article-title>Service-oriented approach to improve interoperability of e-learning systems</article-title>
          .
          <source>In: 2013 IEEE 13th International Conference on Advanced Learning Technologies</source>
          . pp.
          <fpage>341</fpage>
          -
          <lpage>345</lpage>
          (
          <year>2013</year>
          ). https://doi.org/10.1109/ICALT.
          <year>2013</year>
          .105
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          19.
          <string-name>
            <surname>Koc-Januchta</surname>
            ,
            <given-names>M.M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Schönborn</surname>
            ,
            <given-names>K.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Tibell</surname>
            ,
            <given-names>L.A.E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chaudhri</surname>
            ,
            <given-names>V.K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Heller</surname>
            ,
            <given-names>H.C.</given-names>
          </string-name>
          :
          <article-title>Engaging with biology by asking questions: Investigating students' interaction and learning with an artificial intelligence-enriched textbook</article-title>
          .
          <source>Journal of Educational Computing Research</source>
          <volume>58</volume>
          ,
          <fpage>1190</fpage>
          -
          <lpage>1224</lpage>
          (
          <year>2020</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          20.
          <string-name>
            <surname>Ni</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bao</surname>
            ,
            <given-names>Q.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Li</surname>
            ,
            <given-names>X.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Qi</surname>
            ,
            <given-names>Q.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Denny</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Warren</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Witbrock</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Liu</surname>
          </string-name>
          , J.: Deepqr:
          <article-title>Neural-based quality ratings for learnersourced multiple-choice questions</article-title>
          .
          <source>ArXiv abs/2111</source>
          .10058 (
          <year>2021</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          21.
          <string-name>
            <surname>Pollari-Malmi</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Guerra</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Malmi</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sirkiä</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          :
          <article-title>On the value of using an interactive electronic textbook in an introductory programming course</article-title>
          .
          <source>In: Proceedings of the 17th Koli Calling International Conference on Computing Education Research</source>
          . p.
          <fpage>168</fpage>
          -
          <lpage>172</lpage>
          . Koli Calling '
          <volume>17</volume>
          ,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery, New York, NY, USA (
          <year>2017</year>
          ). https://doi.org/10.1145/3141880.3141890, https://doi.org/10.1145/3141880.3141890
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          22.
          <string-name>
            <surname>Rahdari</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Thaker</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barria-Pineda</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          :
          <article-title>Knowledge-driven wikipedia article recommendation for electronic textbooks</article-title>
          .
          <source>In: EC-TEL</source>
          (
          <year>2020</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          23.
          <string-name>
            <surname>Ritter</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , Fisher, J.,
          <string-name>
            <surname>Lewis</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Finocchi</surname>
            ,
            <given-names>S.B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hausmann</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fancsali</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>What's a textbook? envisioning the 21st century k-12 text</article-title>
          . In: iTextbooks@AIED (
          <year>2019</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          24.
          <string-name>
            <surname>Rößling</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Naps</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hall</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Karavirta</surname>
            ,
            <given-names>V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kerren</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Leska</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Moreno</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Oechsle</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rodger</surname>
            ,
            <given-names>S.H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Urquiza-Fuentes</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Velázquez-Iturbide</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          :
          <article-title>Merging interactive visualizations with hypertextbooks and course management</article-title>
          .
          <source>SIGCSE Bull</source>
          .
          <volume>38</volume>
          (
          <issue>4</issue>
          ),
          <fpage>166</fpage>
          -
          <lpage>181</lpage>
          (
          <year>2006</year>
          ). https://doi.org/10.1145/1189136.1189184
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          25.
          <string-name>
            <surname>Sirkiä</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          :
          <article-title>Jsvee kelmu: Creating and tailoring program animations for computing education</article-title>
          .
          <source>Journal of Software: Evolution and Process</source>
          <volume>30</volume>
          (
          <issue>2</issue>
          ) (
          <year>2018</year>
          ), https://onlinelibrary.wiley.com/doi/abs/10.1002/smr.1924
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          26.
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Evaluation of topic-based adaptation and student modeling in quizguide</article-title>
          .
          <source>User Modeling and User-Adapted Interaction</source>
          <volume>25</volume>
          ,
          <fpage>371</fpage>
          -
          <lpage>424</lpage>
          (
          <year>2015</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          27.
          <string-name>
            <surname>Thaker</surname>
            ,
            <given-names>K.M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>He</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>Concept enhanced content representation for linking educational resources</article-title>
          .
          <source>In: 2018 IEEE/WIC/ACM International Conference on Web Intelligence (WI)</source>
          . pp.
          <fpage>413</fpage>
          -
          <lpage>420</lpage>
          (
          <year>2018</year>
          ). https://doi.org/10.1109/WI.
          <year>2018</year>
          .
          <volume>00</volume>
          -
          <fpage>59</fpage>
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          28.
          <string-name>
            <surname>Vihavainen</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vikberg</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Luukkainen</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pärtel</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Scafolding students' learning using test my code</article-title>
          .
          <source>In: Proceedings of the 18th ACM Conference on Innovation and Technology in Computer Science Education</source>
          . p.
          <fpage>117</fpage>
          -
          <lpage>122</lpage>
          . ITiCSE '13,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery, New York, NY, USA (
          <year>2013</year>
          ). https://doi.org/10.1145/2462476.2462501
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          29.
          <string-name>
            <surname>Walker</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wong</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fialko</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Restrepo</surname>
            ,
            <given-names>M.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Glenberg</surname>
            ,
            <given-names>A.M.:</given-names>
          </string-name>
          <article-title>Embrace: Applying cognitive tutor principles to reading comprehension</article-title>
          .
          <source>In: International Conference on Artificial Intelligence in Education</source>
          . pp.
          <fpage>578</fpage>
          -
          <lpage>581</lpage>
          . Springer (
          <year>2017</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          30.
          <string-name>
            <surname>Walker</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wylie</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Danielescu</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rodriguez</surname>
            <given-names>III</given-names>
          </string-name>
          ,
          <string-name>
            <given-names>J.P.</given-names>
            ,
            <surname>Finn</surname>
          </string-name>
          , E.:
          <article-title>Balancing student needs and learning theory in a social interactive postdigital textbook</article-title>
          . In:
          <article-title>End-user considerations in educational technology design</article-title>
          , pp.
          <fpage>141</fpage>
          -
          <lpage>159</lpage>
          . IGI Global (
          <year>2018</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          31.
          <string-name>
            <surname>Weber</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <string-name>
            <surname>ELM-ART</surname>
          </string-name>
          :
          <article-title>An adaptive versatile system for web-based instruction</article-title>
          .
          <source>International Journal of Artificial Intelligence in Education</source>
          <volume>12</volume>
          (
          <issue>4</issue>
          ),
          <fpage>351</fpage>
          -
          <lpage>384</lpage>
          (
          <year>2001</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref32">
        <mixed-citation>
          32.
          <string-name>
            <surname>Xu</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Warschauer</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Exploring young children's engagement in joint reading with a conversational agent</article-title>
          .
          <source>In: Proceedings of the Interaction Design and Children Conference</source>
          . p.
          <fpage>216</fpage>
          -
          <lpage>228</lpage>
          . IDC '20,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery, New York, NY, USA (
          <year>2020</year>
          ). https://doi.org/10.1145/3392063.3394417
        </mixed-citation>
      </ref>
      <ref id="ref33">
        <mixed-citation>
          33.
          <string-name>
            <surname>Zingaro</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Cherenkova</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Karpova</surname>
            ,
            <given-names>O.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Petersen</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          :
          <article-title>Facilitating code-writing in PI classes</article-title>
          .
          <source>In: Proceeding of the 44th ACM Technical Symposium on Computer Science Education</source>
          . p.
          <fpage>585</fpage>
          -
          <lpage>590</lpage>
          . SIGCSE '
          <volume>13</volume>
          ,
          <string-name>
            <surname>Association</surname>
          </string-name>
          for Computing Machinery, New York, NY, USA (
          <year>2013</year>
          )
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>