XML/XML Schema/notation

xs:notation and xs:enumeration

   <source lang="xml">

<?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

 <xs:notation name="pdf" public="application/pdf" system="file:///usr/bin/acroread" />
 <xs:simpleType name="graphicalFormat">
   <xs:restriction base="xs:NOTATION">
     <xs:enumeration value="pdf" />
   </xs:restriction>
 </xs:simpleType>

</xs:schema>

</source>