Metadata link vocabulary

The properties in this vocabulary are usable in the metadata [^link^] element's rel and properties attributes.

The prefix URL for referencing these properties is http://idpf.org/epub/vocab/package/link/#.

Link relationships

The following values can be used in the link element rel attribute to establish the relationship of the resource referenced in the href attribute.

alternate
Name: alternate
Description:

The alternate keyword is a subset of the HTML alternate keyword for links. It differs as follows:

  • It MUST NOT be paired with other keywords.
  • If an alternate link is included in the [=package document=] metadata, it identifies an alternate representation of the package document in the format specified in the media-type attribute.
  • If an alternate link is included in a [^collection^] element's metadata, it identifies an alternate representation of the collection in the format specified in the media-type attribute.
  • [=Reading systems=] do not have to generate hyperlinks for alternate links.
Cardinality: Zero or more
Extends: Only applies to the EPUB publication or collection. MUST NOT be used when the refines attribute is present.
Example: <link rel="alternate" href="package.json" media-type="application/json-ld"/>
marc21xml-record (deprecated)

Use of the marc21xml-record keyword is deprecated. It is replaced by the record keyword with the media-type attribute value "application/marcxml+xml".

Refer to the marc21xml-record property definition in [[!epubpublications-30]] for more information.

mods-record (deprecated)

Use of the mods-record keyword is deprecated. It is replaced by the record keyword with the media-type attribute value "application/mods+xml".

Refer to the mods-record property definition in [[!epubpublications-30]] for more information.

onix-record (deprecated)

Use of the onix-record keyword is deprecated. It is replaced by the record keyword with the properties attribute value onix.

Refer to the onix-record property definition in [[!epubpublications-30]] for more information.

record
Name: record
Description:

Indicates that the referenced resource is a metadata record.

The media type of the record MUST be identified in the media-type attribute when this keyword is specified.

For a list of commonly linked metadata record types, refer to the EPUB Linked Metadata Guide

If the type of record cannot be identified from the media type, an identifier property can be assigned in the properties attribute.
Cardinality: Zero or more
Extends: Only applies to the [=EPUB publication=] or collection. MUST NOT be used when the refines attribute is present.
Example: <link rel="record" href="book/52.atom" media-type="application/atom+xml;type=entry;profile=opds-catalog"/>
voicing
Name: voicing
Description:

Indicates that the referenced audio file provides an aural representation of the expression or resource (typically, the title or creator) specified by the refines attribute.

The media type of the audio file MUST be identified in the media-type attribute when this keyword is specified.
Cardinality: Zero or more
Extends: All properties. The refines attribute MUST be present when this value is used.
Example: <link refines="#title" rel="voicing" media-type="audio/mpeg" href="title.mp3" />
xml-signature (deprecated)

Use of the xml-signature keyword is deprecated. It is not replaced by another linking method.

Refer to the xml-signature property definition in [[!epubpublications-30]] for more information.

xmp-record (deprecated)

Use of the xmp-record keyword is deprecated.

Refer to the xmp-record property definition in [[!epubpublications-30]] for more information.

Link properties

The following values can be used in the [^link^] element's properties attribute to establish the type of record a referenced resource represents. These values are provided for record formats that cannot be uniquely identified by their media type.

onix
Name: onix
Description: The onix property indicates the referenced resource is an ONIX record [[!onix]].
Example: <link rel="record" href="pub/meta/nor-wood-onix.xml" media-type="application/xml" properties="onix"/>