Defined to allow an editor to specify an explicit (non machine-generated) line-break
This element is restricted to a very few contexts, for example, inside titles (such as <title>), <institution>s, and inside table cells (<td>s and <th>s).
EMPTY
This is an EMPTY element
<aff>, <alt-title>, <article-title>, <chem-struct>, <collab>, <disp-formula>, <inline-supplementary-material>, <institution>, <kwd>, <product>, <related-article>, <sig-block>, <subject>, <subtitle>, <target>, <td>, <th>, <title>, <trans-subtitle>, <trans-title>, <xref>
format3.ent