Bibliographic identifier for a document that does not have traditional printed page numbers.
This element acts in the same way as a page identifier for a document that does not have traditional page numbers; the value could be an online identifier, DOI, etc., for example, “E70”. For example, it provides an identifier such as a DOI for a related article.
External Identifier: This element holds an external identifier, assigned to a book or book part by a publisher, an archive, or library to help cite a book or book part that is born digital and will never have page numbers. The contents of this element should not be confused with the @id attribute, which holds an internal document identifier that can be used by software to preform a simple link.
<!ELEMENT elocation-id (#PCDATA) >
Text, numbers, or special characters
<book-part-meta>, <element-citation>, <mixed-citation>, <product>, <related-article>, <related-object>
...
<book-part-meta>
...
<contrib-group>...</contrib-group>
<pub-date date-type="pub" iso-8601-date="2002-08-28">
<day>28</day>
<month>08</month>
<year>2002</year>
</pub-date>
<elocation-id>E27</elocation-id>
<pub-history>
<date date-type="accepted" iso-8601-date="2002-08-22">
<day>22</day>
<month>08</month>
<year>2002</year>
</date>
</pub-history>
</book-part-meta>
...