libxml2/test/SVG/structure01.xml

<?xml version="1.0" standalone="yes"?>
<parent xmlns="http://someplace.org"
       xmlns:svg="http://www.w3.org/Graphics/SVG/svg-19990412.dtd">
   <!-- parent stuff here -->
   <svg:svg width="5cm" height="8cm">
      <svg:ellipse major="200" minor="130" />
   </svg:svg>
   <!-- ... -->
</parent>