XML File Example

<!DOCTYPE DWELLING SYSTEM "dwelling.dtd" [
   <!ENTITY person "X">
   <!ENTITY dog "D">
   <!ENTITY cat "C">
   <!ELEMENT ROOM (FURNITURE? & ITEM)+ >
   <!ELEMENT FURNITURE (ITEM+)>
   <!ELEMENT ITEM (#PCDATA)>]>
<DWELLING>
   <ROOM Name="The Kitchen">
	<FURNITURE>Table</FURNITURE >
   	&dog; &person;
	<ITEM>Dish</ITEM>
   </ROOM> 
   <ROOM Name="Marvin's Room">
   	&cat;
	<FURNITURE">
		Chair
        	<ITEM>Coin</ITEM>
        </FURNITURE >
   </ROOM> 
</DWELLING>