<!ELEMENT time-stamp (#PCDATA %time-stamp-elements;)* >
(#PCDATA | day | era | month | season | year | x)*
...
<ref>
<nlm-citation publication-type="commun">
<person-group person-group-type="author">
<string-name><surname>Harris</surname>,
<given-names>Pat</given-names></string-name>
</person-group>
<article-title>New Z39.50 resource [Internet]</article-title>
<source>Message to: Karen Patrias</source>
<year iso-8601-date="1998-02-27T13:18">1998</year>
<month>02</month>
<day>27</day>
<time-stamp>1:18 pm</time-stamp>
<access-date>cited 1998 Feb 28</access-date>
<comment>[about 2 screens]</comment>
</nlm-citation>
</ref>
...
Journal Archiving and Interchange Tag Library NISO JATS Draft Version 1.1d2
Version of December 2014