The identifier of a journal, book, conference proceedings, or other publication that is (or contains) the target of the <related-object>
Used along with @source-id-type to identify the publication that is (or contains) the target of the <related-object> element. The @source-id might contain an ISBN as content, and the @source-id-type should indicate that this ID is an ISBN.
| Value | Meaning |
|---|---|
| Text, numbers, or special characters | The identifier of the source for the <related-object> |
| Restriction: This attribute may be specified if the element is used. | |