Content Item Relations
Content items can have relations to other content items. What specific
kinds of relations a content item is allowed to have depends upon
content type, and is defined in the content-type
resource: you may already have noticed the
<ref-relation-type-group name="attachments"/>
element in the content type definitions we have looked at. For a
detailed discussion of content item relations, including their
definition in the content-type
resource, see
Relations.