rement" id="must-requirement_xref44">must</a>
        not contain replaceable character data
        as described in this reference; instead they 
        <a href="terminology.html#must-requirement" id="must-requirement_xref45">must</a>
        conform to all syntax constraints described in the XML
        specification <a href="references.html#refsXML" id="refsXML_xref7">[XML]</a>.</p>
      </dd>
      <dt><dfn id="non-replaceable-character-data" title="non-replaceable-character-data">non-replaceable char