<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" [

    <!ENTITY myURI "http://www.websitedev.de/xhtml/xhtml1/">

]> <html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>[ #431898 ] Tidy messes up X(HT)ML documents</title>
</head>
<body>
<p><a href="&myURI;">Test</a></p>
</body>
</html>