1  <?xml version="1.0"?>
 2  
 3  <?xml-stylesheet   href="doc.xsl"
 4     type="text/xsl"   ?>
 5  
 6  <!DOCTYPE doc SYSTEM "doc.dtd">
 7  
 8  <doc>Hello, world!<!-- Comment 1 --></doc>
 9  
10  <?pi-without-data     ?>
11  
12  <!-- Comment 2 -->
13  
14  <!-- Comment 3 -->