<?xml version="1.0" encoding="iso-8859-1"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0" datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
  <include href="http://example.com/xml.rng"/>
  <start>
    <ref name="include"/>
  </start>
  <define name="include">
    <element name="include">
      <text/>
    </element>
  </define>
</grammar>