document-id-type Related Object 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.
OPTIONAL on element: <related-object>
Value Meaning
The type of document identifier of the related object, for example, a DOI The type of document identifier named in the @document-id attribute for a (<related-object>) element. This attribute qualifies the @document-id attribute.
Restriction This is an optional attribute; there is no default.