<!ELEMENT issn-l (#PCDATA %issn-l-elements;)* >
(#PCDATA | x)*
...
<journal-meta>
<journal-id journal-id-type="pmc">pnas</journal-id>
<journal-id journal-id-type="pubmed">Proc Natl Acad Sci U S A</journal-id>
<journal-id journal-id-type="publisher">PNAS</journal-id>
<issn publication-format="print">0027-8424</issn>
<issn publication-format="electronic">1091-6490</issn>
<issn-l>0027-8424</issn-l>
<publisher>
<publisher-name>The National Academy of Sciences</publisher-name>
</publisher>
</journal-meta>
...
Journal Archiving and Interchange Tag Library NISO JATS Draft Version 1.1d2
Version of December 2014