document-id-type Document Identifier Type

Type of document identifier (for example, a DOI or a publisher’s identifier) named in the @document-id attribute of the <related-object> element to identify a document, for example, “doi”.
OPTIONAL on element: <related-object>
Value Meaning
The type of document identifier of the related object, for example, a DOI (doi). Names/describes the type of document identifier for the @document-id attribute named in a <related-object> element. This attribute qualifies the @document-id attribute.
Restriction @document-id-type is an optional attribute; there is no default.