michael@0: <?xml version="1.0"?>
michael@0: 
michael@0: <!DOCTYPE zoo [
michael@0:     <!ATTLIST species id ID #REQUIRED>
michael@0: ]>
michael@0: 
michael@0: <zoo>
michael@0:   <class>
michael@0:     <name>Reptiles</name>
michael@0:     <species id="Chamaeleo-chamaelon" name="Chameleon" specimens="2"/>
michael@0:   </class>
michael@0:   <class>
michael@0:     <name>Birds</name>
michael@0:     <species id="Dromaius-novaehollandiae" name="Emu" specimens="12"/>
michael@0:     <species id="Tyto-alba" name="Barn Owl" specimens="4"/>
michael@0:     <species id="Corvus-corax" name="Raven" specimens="0"/>
michael@0:     <location>Aviary</location>
michael@0:   </class>
michael@0: </zoo>