<doc
  xmlns:its="http://www.w3.org/2005/11/its" 
  xmlns:dbk="http://docbook.org/ns/docbook" >
 <its:rules version="2.0">
  <its:externalResourceRefRule selector="//dbk:imagedata | //dbk:audiodata |  //dbk:videodata" externalResourceRefPointer="@fileref"/>
 </its:rules>
 <dbk:mediaobject>
  <dbk:videoobject>
   <dbk:videodata fileref="movie.avi"/>
  </dbk:videoobject>
  <dbk:imageobject>
   <dbk:imagedata fileref="movie-frame.gif"/>
  </dbk:imageobject>
  <dbk:textobject>
   <dbk:para>This video illustrates the proper way to assemble an inverting time distortion
       device. </dbk:para>
   <dbk:warning>
    <dbk:para> It is imperative that the primary and secondary temporal couplings not be
         mounted in the wrong order. Temporal catastrophe is the likely result. The
         future you destroy may be your own. </dbk:para>
   </dbk:warning>
  </dbk:textobject>
 </dbk:mediaobject>
</doc>