1 <?xml version="1.0"?>
   2 <!DOCTYPE note [                           
   3 <!ELEMENT note    (to,from,heading,body)>
   4 <!ELEMENT to      (#PCDATA)>
   5 <!ENTITY writer "Albert Einstein">
   6 <!ENTITY author "Albert Einstein">
   7 <!ENTITY test SYSTEM "test.txt">
   8 <!ENTITY % test2 "test2">
   9 <!ENTITY author "author">
  10 ]>                         
  11 <note>
  12 <to>&writer;</to>
  13 
  14 </note>