The subordinate name of a journal component such as an article
Within a bibliographic reference citation, the subtitle cannot be preserved separately. For citations using <citation>, it is possible to place the subtitle with the title in the <article-title> element (or the <source> element for book titles, proceedings titles, and other titles) or to leave it as untagged data characters within the text of the reference. For references using <nlm-citation>, the subtitle must be included with the title, since that reference model does not permit untagged text. Although this DTD cannot enforce either practice when using <citation>, retrieval performance will be enhanced if the subtitle is consistently placed in the <article-title> element (or the <source> element for book titles, proceedings titles, and other titles) for all cited material, so this is considered best practice.
<!ELEMENT subtitle (#PCDATA %title-elements;)* >
Any combination of:
<article> <front> <article-meta> <title-group> <article-title>Adaptins<fn id="FN206"> <p>Online version of this essay contains supplemental tabular material.</p> </fn> </article-title> <subtitle>The Final Recount</subtitle> </title-group> ... </article-meta> </front> ... </article>