This element is used in two ways:
<!ELEMENT supplement (#PCDATA %supplement-elements;)* >
Any combination of:
<article-meta> Article Metadata; <citation> Citation; <product> Product Information; <related-article> Related Article Information
...
<article-meta>
...
<volume>52</volume>
<issue>1</issue>
<supplement>1</supplement>
<fpage>437</fpage>
<lpage>467</lpage>
...
</article-meta>
...
articlemeta.ent