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.

Used on Element: <related-object>

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@document-id-type is an optional attribute; there is no default.