<?xml version="1.0"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0"
         datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
         
<include href="opf20.rng"/>
<include href="opf12.rng"/>

<start>
  <choice>
    <ref name="OPF20.package-element"/>
    <ref name="OPF12.package-element"/>
  </choice>
</start>
	
</grammar>