raged to use XML declarations in all their documents. Such a declaration is required
when the character encoding of the document is other than the default UTF-8 or
UTF-16.</p>

<h3><a name="well-formed" id="well-formed">3.1.2 Using XHTML with
other namespaces</a></h3>

<p>The XHTML namespace may be used with other XML namespaces
as per <a href="#ref-xmlns">[XMLNAMES]</a>, although such
documents are not strictly conforming XHTML 1.0 documents as
defined above. Future work by W3C will address ways to specify