Editor's Draft 15 January 2015
NOTE The EPUB Working Group is developing this profile through a series of iterative releases. This document represents the product of the fifth iteration of this development cycle. |
This version:
http://www.idpf.org/epub/profiles/edu/spec/edupub-20150115.html
Latest version:
http://www.idpf.org/epub/profiles/edu/spec/
Previous version:
http://www.idpf.org/epub/profiles/edu/spec/edupub-20141127.html
Copyright © 2014-2015 International Digital Publishing Forum™
All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and dissemination of this work with changes is prohibited except with the written permission of the International Digital Publishing Forum (IDPF).
EPUB® is a registered trademark of the International Digital Publishing Forum.
Editors
Garrish, Matt (Invited Expert)
Gylling, Markus (IDPF)
Levenson Hirschman, Yonah (Pearson)
Siegman, Tzviya (Wiley)
Stroup, David (Pearson)
Status of this Document
This document is an Editor's Draft, produced by the IDPF EPUB 3 Working Group, based on an initial member submission by Pearson in December, 2013.
Unlike traditional IDPF specifications, the development of this profile is anticipated to follow an agile model, with core features and functionality defined in the initial release and less critical features -- or features that require more time to properly detail and implement properly -- following later.
Functionality and features in the profile will continue to be evaluated over the duration of the development cycle and could be modified or deprecated based on real-world usage.
This document may be updated, replaced, or rendered obsolete by other documents at any time. Its contents do not necessarily reflect the consensus of the Working Group.
Open issues in this draft
This section will be removed when this document leaves draft status. Open issues in this draft include the following:
Table of Contents
2.2 Reading System Conformance
3.3 Multiple-Rendition Publications
3.4 Teacher's Editions and Guides
4.7 Distributable Educational Objects
8. Assessments, Outcomes and Analytics
8.1 Integration with IMS Caliper, QTI, and LTI
9.2.2 audience/EducationalAudience
9.2.4 EducationalAudience/educationalRole
Appendix D. Educational Metadata Properties
Appendix E. Educational Metadata Mappings
This section is informative
Digital content in education has the potential to significantly improve learning outcomes, as it can better support accessibility, adapt to individual learning modes, increase engagement and experiential learning through interactivity, provide immediate assessments and analytics, and increase social connectivity.
To this end, the EDUPUB profile defined in this document represents the effort to adapt the functionality of the EPUB® 3 format to the unique structural, semantic and behavioral requirements of educational publishing.
The profile builds on the EPUB 3 specification in the following ways:
Refer to the EPUB Specifications for definitions of EPUB-specific terminology used in this document.
The following typographic conventions are used in this specification:
markup
All markup (elements, attributes, properties), code (JavaScript, pseudo-code), machine processable values (string, characters, media types) and file names are in red-orange monospace font.
markup
Links to markup and code definitions are underlined and in red-orange monospace font. Only the first instance in each section is linked.
http://www.idpf.org/
URIs are in navy blue monospace font.
hyperlink
Hyperlinks are underlined and in blue.
[reference]
Normative and informative references are enclosed in square brackets.
Term
Terms defined in the Terminology are in capital case.
Informative markup examples are in monospace font.
NOTE
Informative notes are preceded by a "Note" header.
The keywords must, must not, required, shall, shall not, should, should not, recommended, may, and optional in this document are to be interpreted as described in [RFC2119].
All sections of this specification are normative except for examples, or except for sections identified by the informative status label "This section is informative". The application of informative status to sections and appendices applies to all child content and subsections they may contain.
As a profile of EPUB 3, these guidelines build on the functionality defined in the following core specifications:
Unless explicitly overridden, this profile inherits all requirements defined in these specifications.
EDUPUB-compliant Publications are always valid EPUB 3 Publications, but, due to the additional production requirements detailed in this document, the reverse is not necessarily true.
In addition to meeting the requirements specified in EPUB Publications [Publications301], an EPUB Publication conformant with this profile must meet all of the following criteria:
In addition to meeting the requirements specified in EPUB Publications [Publications301], an EPUB Reading System conformant with this profile must meet all of the following criteria:
The primary focus of this version of the EDUPUB profile is on the creation of reflowable XHTML-based EPUB Publications.
Reflowable Renditions of the content are typically more accessible than pre-paginated Renditions, making the content more widely accessible to a broader range of students.
The semantics defined in this profile are also better suited to annotating markup structures that have not been artificially broken by page boundaries, and the requisite chunking of content into separate files. Navigation is similarly simplified for users of assistive technologies when content structures are not broken apart by pagination.
The use of reflowable Renditions is therefore strongly recommended.
The creation of fixed layouts is neither encouraged nor discouraged in EDUPUB-compliant EPUB Publications.
Guidelines for the production of Fixed-Layout Publications will be considered in a future version of the profile.
In the interim, the creation of accessible XHTML-based Fixed-Layout Publications is strongly encouraged.
The inclusion of an accessible Rendition is required when the Default Rendition is image-based or does not have a logical reading order (e.g., fixed layouts where the markup order of components does not match the visual reading order).
EDUPUB Publications may contain more than one Rendition of the content.
In such cases, the EPUB Container must conform to the requirements for multiple-Rendition EPUB Publications defined in [MultipleRenditions].
A Rendition Mapping Document should be included in multiple-Rendition EPUB Publications to allow Users to switch from one Rendition to another without losing their place.
Teacher's editions and guides are important tools in educational instruction. Both provide guidance to the teacher, but a teacher's edition represents a superset of the work the students are using, while a teacher's guide typically provides general instruction and guidance on the curriculum (i.e., there is no student edition).
This section does not introduce special processing requirements for either. In particular, it is assumed that teacher and student editions are packaged separately, as EPUB ‒ and the Open Web Platform generally ‒ does not provide a means of reliably hiding content from readers.
An EPUB Publication that represents a teacher's edition must be identified as such in the package metadata of each of its Renditions by including a dc:type element [Publications301] with the value "teacher-edition".
The following example shows an EPUB Publication identified as a teacher's edition
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:type>teacher-edition</dc:type>
…
</metadata>
An EPUB Publication that represents a teacher's guide must be identified with the value "teacher-guide".
The following example shows an EPUB Publication identified as a teacher's guide
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:type>teacher-guide</dc:type>
…
</metadata>
Teacher's guides and editions will also be identified as compliant with the EDUPUB profile as defined in 9.1 Profile Identification, so must conform to all requirements in this specification.
As a teacher's edition represents an annotated version of a student edition, it should identify the corresponding student edition in a dc:source element:
The following example shows an EPUB Publication identified as a teacher's guide
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:source>urn:isbn:9780000000001</dc:source>
…
</metadata>
NOTE
As teacher's guides do not have student editions, this recommendation does not apply to them.
The EDUPUB content model does not include structural semantics specifically for the construction of teacher editions and guides, but the inclusion of such semantics is under consideration for a future version of the profile.
The use of semantics defined in 5. Structural Semantics is recommended, where applicable.
The standardization of CSS class names for controlling the appearance of teacher-specific content is under consideration for a future version of the profile.
As a teacher's edition contains both the text of the student edition together with annotations, answers and other instructional aids for the teacher, there is a need to accessibly differentiate the teacher content from the content that all the students will have access to beyond visual CSS styling.
The use of structural semantics enhances the meaning of the content, but in itself does not indicate who the content was intended for. To address discoverability for users of assistive technologies, all teacher content must include be labeled using the [ARIA] aria-label attribute.
The following example shows an answer section labeled as belonging to the teacher edition
<section epub:type="answers" aria-label="teacher edition content">
…
</section>
This specification does not require specific language for this attribute, but whatever text is used should clearly identify the audience is teachers.
NOTE
As teacher's guides are exclusively for teachers, content does not have to labelled.
The audience may also be specified using the [schema.org] audience property for reliable machine processing (e.g., to selectively hide teacher-only content in a Reading System, or to enable filtering of content prior to distribution). Processing of this metadata is optional.
The following example shows the inclusion of the schema.org audience property to identify that an answers section is intended only for teachers.
<section id="answers01"
aria-label="teacher edition content"
epub:type="answers">
<meta resource="#answers01"
typeof="schema:WebPageElement"
property="schema:audience"
content="teacher"/>
…
</section>
For accessibility purposes, it is strongly recommended that student content not be represented as annotated images in teacher's editions.
This section is informative
This section outlines key content structuring guidelines for the production of EDUPUB-compliant EPUB Publications. Only differences from the core suite of EPUB specifications are noted.
The section element must be used to group sections of related content.
If the root of an XHTML Content Document consists of a single section of content, a section wrapper may be omitted (i.e., the body represents the implied section). Any subsections of the root section must be wrapped in section tags.
Each section should have a heading expressed either in an [HTML5] ranked heading element or an [ARIA] aria-label attribute. Sections must not have more than one heading, and must not combine ranked heading elements and the aria-label attribute.
[HTML5] heading elements must be used to provide headings only for [HTML5] sectioning content.
When using a heading element for a section, the rank must reflect the nesting of that section within the document hierarchy (as noted in 4.3.10 Headings and sections [HTML5]). For example, a top-level section will have an h1 heading, child sections of it will have h2 headings, and so on. Note that untitled sections are included when determining the current heading rank (see 4.3.2 Untitled Sections for more information).
The heading does not have to be the first element of the section, and may be included inside a [HTML5] header element.
The application of headings must reflect the hierarchy regardless of how the content has been chunked for distribution (i.e., it is not necessary that the first section in each file begin with an h1).
The [ARIA] aria-label attribute must not be included on a section if it provides the same text already available in a ranked heading, as it can lead to duplicate announcement of the heading to users of assistive technologies.
NOTE
Refer to 4.13 Common idioms without dedicated elements [HTML5] for suggestions on appropriate markup patterns for subheadings and similar.
If a section of content that would normally be in the document hierarchy does not have a heading (e.g., an untitled introduction) ‒ or sectioning is used to group significant content, such as learning objectives, that a reader using an AT would need access to ‒ the [ARIA] aria-label attribute should be used to provide an accessible name.
Adding this attribute allows users of assistive technologies to navigate to the section despite the lack of a heading, in addition to giving meaningful context.
Despite the lack of an explicit ranked heading, untitled sections are still part of the document's structural hierarchy and affect the heading rank of any child sections they contain. For example, the untitled section in the following example counts as the second level in the document outline, so the next ranked heading is an h3 even though no h2 appears in the markup:
<section
epub:type="chapter">
<h1>Chapter 1: Lists</h1>
<section aria-label="Chapter body">
<section
epub:type="learning-objectives">
<h3>1.2 Learning Objectives List</h3>
When the document hierarchy exceeds six levels of nesting, re-use the h6 element for the seventh nesting level and deeper. Avoid deep nesting of content, if possible, as the flattened structure below the sixth heading level impacts on the ability of users of assistive technologies (AT) to move through the document without repeatedly returning to the table of contents.
Do not use heading elements where the heading does not reflect the document hierarchy, as this use will impact on movement by AT users (e.g., inside figure captions).
When nesting aside or article elements with headings inside a section, the heading rank must start one level lower than the containing section (e.g., if the section has an h3 heading, the aside will start with an h4 heading).
The use of RDFa Lite [RDFaLite] is recommended for enriching content.
Examples of content enrichment in this specification use RDFa Lite syntax.
If a reflowable Rendition has a print representation, or is derived from a digital pre-paginated Rendition, it is strongly recommended that page break markers be included in the Rendition to allow students to synchronize their reading with the alternate representation.
The pagination source must be identified using the dc:source and source-of properties [Publications301] when including markers. The source may be a reference to the EPUB Publication if pagination is derived from another Rendition in the Container.
A page-list nav [ContentDocs301] must be included in the EPUB Navigation Document when page breaks are included. See 3.3 Page list for more information.
Although any core media type image format defined in 5.1 Core Media Types [Publications301] may be used in an EPUB Publication, the following guidelines are suggested:
This section is informative
In educational contexts, there is a need to distribute and consume not only complete publications, but components of publications and other objects not necessarily originating within a publication. Such "distributable objects" could be complete EPUB Content Documents (for example, a chapter of a book), sections of such a document (for example, an exercise or a set of learning objectives), media resources (such as a video or an interactive feature), or a combination of such resources that are not necessarily contiguous within the parent EPUB Publication.
The following section provides the specifications that pertain to creating Distributable Objects [DistributableObjects] that are intended for education and which conform to this specification.
Distributable educational objects embedded in EDUPUB-compliant EPUB Publications are identified using the distributable-object collection element [DistributableObjects].
In addition to the required metadata defined in [DistributableObjects], each collection must describe its object according to the metadata requirements in 9. Metadata, and include an identifier dc:type element [Publications301] with the value "edupub".
EPUB Publications conformant with this profile may include any other type of distributable object, provided the object does not conflict with the requirements of this specification.
NOTE These terms will remain under active development for the duration of the EDUPUB initiative. It is anticipated that more terms will be added in subsequent iterations. Similarly, some terms may be deprecated or removed. |
The EDUPUB profile includes a set of structural semantic terms and content production rules designed to standardize the markup of educational materials.
The formal definitions of these terms, and requirements for their use, are defined in the normative EDUPUB Structural Semantics [EDUPUBStructure] document.
Publishers are strongly recommended to represent all publication structures using the markup and terms defined in the [EDUPUBStructure] document.
Following is a categorized list of the terms available, with links to their definitions. (Note: categorization does not imply usage restrictions, particularly in the case of sectioning terms.)
A complete table of contents that fully reflects the heading hierarchy of the work is important for all readers, as it ensures that students are able to efficiently access any section necessary.
Consequently, a toc nav [ContentDocs301] with links to the full document heading hierarchy must be included in every EPUB Publication conformant to this profile.
The epub:type attribute may be attached to list items in the toc nav to enable Reading Systems and other processing agents to more precisely identify the structure of the work.
A brief table of contents represents a shortened version of the toc nav element [ContentDocs301], typically where sub-levels of the document hierarchy have been removed for clarity.
The toc-brief nav inherits the structural production requirements of the toc nav. Nesting of link lists is allowed, as there are no requirements on how much or little of the document hierarchy to include in the brief the table of contents.
The inclusion of a brief table of contents is optional, but only one toc-brief nav is allowed in the EPUB Navigation Document when present.
The addition of a brief table of contents to the EPUB Navigation Document does not alter the requirement to include a full table of contents in the toc nav.
The toc-brief semantic may be used within the content of an EPUB Publication (e.g., at the start of each chapter), in which case the production requirements for use in the EPUB Navigation Document do not apply.
EPUB Publications conformant to this profile should provide lists of illustrations (figures), tables and audio and video content in the EPUB Navigation Document when such structures are included.
A figure list is identified by adding the "loi" term to a nav element, a table list by the "lot" term, and audio and video lists by the "loa" and "lov" terms, respectively.
If page break markers are included in the EPUB Publication, a page-list nav [ContentDocs301] must be included in the EPUB Navigation Document.
Likewise, if the EPUB Publication is statically paginated through the use of fixed layout pages, a page-list nav must be included, even if no print equivalent exists.
EPUB Scriptable Components [EPUBSC] may be included in EDUPUB-compliant Publication, and must be integrated and identified as defined in that specification.
NOTE
Support will be integrated in a future iteration of this specification.
This section is informative
A document that presents the best practice recommendations for using IMS Learning Tools Interoperability™ (LTI™), IMS Caliper Analytics™ and IMS Question & Test Interoperability™ (QTI™) based content within an EPUB3 context, is available at [IMSGuide].
NOTE
Further recommendations and best practices for integrating EDUPUB content with assessments, outcomes and analytics services is planned to be integrated in a future iteration of this specification.
An EPUB Publication conforming to this specification must be identified as such in the package metadata of each of its Renditions by including a dc:type element [Publications301] with the value "edupub".
The following example shows an EPUB Publication identified as EDUPUB-conformant.
<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
<dc:type>edupub</dc:type>
…
</metadata>
Educational metadata is needed to describe the suitability of content for educational settings, and to facilitate search and retrieval.
The [schema.org] CreativeWork type includes educational metadata properties that Authors can set in the EPUB Package Document to identify the nature and suitability of the content. In addition, the [schema.org] EducationalAudience type can be used to express the intended audience of the work.
This specification does not require the use of any of these properties, but usage recommendations in the following subsections are suggested based on the intended audience of the publication: schools, higher education, and professional/technical/corporate.
In some cases, a default value is assumed for educational properties when they are not specified in the metadata. Default values are indicated in the allowed values sections.
NOTE
A mapping between schema.org and IMS metadata properties is provided in Appendix E.1.
Allowed Value(s) "schema:audience" (Refer to the [SchemaGuide].) No default value. Cardinality Exactly one Usage Professional/Technical/Corporate: optional Schools: recommended Higher Education: recommended Example <meta property="schema:audience" id="aud01">schema:audience</meta> <meta refines="#aud01" property="rdf:type">http://www.schema.org/EducationalAudience</meta> <meta property="educationalRole" refines="#aud01">Teacher</meta> |
Allowed Value(s) "schema:educationalAlignment" (Refer to the [SchemaGuide].) No default value. Cardinality One or more Usage Professional/Technical/Corporate: optional Schools: recommended Higher Education: recommended Example <meta id="ea02" property="schema:educationalAlignment">schema:educationalAlignment</meta> <meta refines="#ea02" property="schema:alignmentType">teaches</meta> <meta refines="#ea02" property="schema:targetName"> Calculate probabilities using the Addition Rules and Multiplication Rules. </meta> <meta refines="#ea02" property="schema:targetUrl"> http://example.com/competency502041 </meta> |
Allowed Value(s) Refer to D.1.1 educationalRole Default value: Student Cardinality Zero or one Usage Professional/Technical/Corporate: Strongly recommended Schools: Strongly recommended Higher Education: Strongly recommended Example <meta property="schema:audience" id="aud01">schema:audience</meta> <meta refines="#aud01" property="rdf:type">http://www.schema.org/EducationalAudience</meta> <meta property="educationalRole" refines="#aud01">Teacher</meta> |
Allowed Value(s) Refer to D.1.3 educationalUse No default value. Cardinality Exactly one Usage Professional/Technical/Corporate: optional Schools: Strongly recommended Higher Education: Strongly recommended Example <meta property="schema:educationalUse">Demonstration</meta> |
Allowed Value(s) Refer to D.1.5 interactivityType Default value: Activity Cardinality Zero or one Usage Professional/Technical/Corporate: recommended Schools: Strongly recommended Higher Education: Strongly recommended Example <meta property="schema:interactivityType">Mixed</meta> |
Allowed Value(s) URL No default value. Cardinality Zero or more Usage Professional/Technical/Corporate: recommended Schools: recommended Higher Education: recommended Example <meta property="schema:isBasedOnUrl">http://www.example.com/book</meta> |
Allowed Value(s) Refer to D.1.6 learningResourceType No default value. Cardinality Exactly one Usage Professional/Technical/Corporate: optional Schools: Strongly recommended Higher Education: Strongly recommended Example <meta property="schema:learningResourceType">Activity</meta> |
Allowed Value(s) A string representing an [ISO8601] duration No default value. Cardinality Zero or one Usage Professional/Technical/Corporate: optional Schools: optional Higher Education: optional Example <meta property="schema:timeRequired">P90M</meta> |
Allowed Value(s) Refer to D.1.4 typicalAgeRange No default value. Cardinality Zero or more Usage Professional/Technical/Corporate: optional Schools: Strongly recommended Higher Education: recommended Example <meta property="schema:typicalAgeRange">16-18</meta> |
Identifying the accessible qualities of an EPUB Publication is of vital importance in educational contexts, as the needs and preferences of students will dictate whether any given Rendition of the content will be sufficiently usable by them in their studies.
The [schema.org] CreativeWork type includes accessibility metadata properties [A11YProperties] that Authors can set in the EPUB Package Document to identify the accessible qualities of a given Rendition of the EPUB Publication.
Each Rendition must identify all applicable accessibility features using the accessibilityFeature property. A recommended list of values to use with this property is maintained at the W3C Web Schemas wiki [A11YProperties]. The property must be repeated for each applicable value.
If the given Rendition contains no accessible features, or the Author is unable to state which apply, a single accessibilityFeature declaration specifying the value "none" must be included.
It is strongly recommended that the other properties be specified whenever applicable.
Refer to the schema.org metadata integration guide [SchemaGuide] more information on how to include these properties in the Package Document.
In distribution contexts that require the use of an ONIX record, the accessibility properties defined in Code List 196 [ONIXCodes] should be specified, as appropriate.
NOTE
A mapping table from the ONIX to schema.org frameworks is available on the a11ymetadata.org site.
Reading Systems must provide a mechanism to ingest ‒ and support the rendering of ‒ annotations that conform to the Open Annotation in EPUB specification [OpenAnnotation].
Support for exporting and synchronizing annotations is optional.
This appendix is informative
A sample CSS file is available at http://www.idpf.org/epub/profiles/edu/res/sample.css
The sample CSS file is provided for informational purposes only. Authors are free to use any CSS class names and styles with their documents.
NOTE
The CSS profile is subject to ongoing change as part of the evolution of the profile.
This appendix is informative
NOTE
Content validation services will be referenced from here in a forthcoming iteration.
This appendix is informative
For informational review of the markup patterns defined in this specification, EPUB Publications conformant to this profile are provided at the EDUPUB samples repository.
These documents are subject to change, and may be added to, and removed, over time.
NOTE The following sections provide recommended vocabularies for use with the schema.org educational metadata properties. These vocabularies are expected to be removed in a future iteration after formal vocabularies are published. |
Additional values from IMS
This appendix is informative
The below table contains a correspondence mapping between the educational metadata terms of schema.org [schema.org] and IMS as described in Appendix E of [IMSGuide].
schema.org term |
IMS term |
GUID [identifier] |
|
targetURL |
Resource URL |
name |
Title [title] |
description |
Description [description] |
keywords |
Keywords [subject] |
typicalAgeRange |
From Grade |
typicalAgeRange |
To Grade |
productID |
ISBN [identifier] |
learningResourceType |
Type [type] |
educationalAudience |
UseType |
educationalUse |
UseType (repeat) |
Thumbnail |
Thumbnail |
educationalAlignment |
Mapping to Curriculum Standards |
AlignmentObject |
Mapping to Curriculum Standards (repeat) |
AlignmentType |
|
educationalRole |
|
timeRequired |
|
interactivityType |
|
useRightsURL |
|
isBasedOnURL |
EPUB has been developed by the International Digital Publishing Forum in a cooperative effort, bringing together publishers, vendors, software developers, and experts in the relevant standards.
The EDUPUB Profile 1.0 specification was prepared by the International Digital Publishing Forum's EPUB Working Group, operating under under the leadership of:
Active members of the working group at the time of publication were:
IDPF Members
Invited Experts/Observers
[A11YProperties] Schema.org Accessibility Metadata Properties.
[ARIA] Accessible Rich Internet Applications (WAI-ARIA) 1.0, J. Craig, et al.
[ContentDocs301] EPUB Content Documents 3.0.1
[CSS21] Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification. Bert Bos, et al. 7 June 2011.
[DCMES] Dublin Core Metadata Element Set, Version 1.1.
[DistributableObjects] EPUB Distributable Objects.
[EDUPUBStructure] EDUPUB Structural Semantics.
[EPUBCFI] EPUB Canonical Fragment Identifier (epubcfi) Specification.
[EPUBSC] EPUB Scriptable Components Packaging and Integration.
[HTML5] HTML5: A vocabulary and associated APIs for HTML and XHTML.
[IDX] EPUB Indexes 1.0.
[JPEG] JPEG Standard (JPEG ISO/IEC 10918-1 ITU-T Recommendation T.81) .
[Manifest] EPUB Manifest Role.
[MediaOverlays301] EPUB Media Overlays 3.0.1.
[MultipleRenditions] EPUB Multiple-Rendition Publications.
[OCF301] Open Container Format 3.0.1.
[ONIXCodes] Onix Code Lists. EDItEUR.
[OpenAnnotation] Open Annotation in EPUB.
[PNG] Portable Network Graphics (PNG) Specification (Second Edition) . David Duce. 10 November 2003.
[Publications301] EPUB Publications 3.0.1.
[RDFaLite] RDFa Lite 1.1. Manu Sporny. 07 June 2012.
[RFC2119] Key words for use in RFCs to Indicate Requirement Levels (RFC 2119) . March 1997.
[RFC3987] Internationalized Resource Identifiers (IRIs) (RFC 3987). M Duerst, et al. January 2005.
[schema.org] schema.org.
[sRGB] IEC 61966-2-1:1999 Multimedia systems and equipment. Colour measurement and management. Colour management. Default RGB colour space. sRGB
[StructureVocab] EPUB 3 Structural Semantics Vocabulary .
[SVG] Scalable Vector Graphics (SVG) 1.1 (Second Edition) . Erik Dahlström, et al. 09 June 2011.
[SchemaGuide] Schema.org Metadata Integration Guide for EPUB 3.