1 <!ELEMENT document ANY>
   2 <!ELEMENT title (#PCDATA)>
   3 <!ELEMENT publisher (#PCDATA)>
   4 <!ELEMENT book (#PCDATA)>
   5 <!ELEMENT bookurn (#PCDATA)>
   6 <!ATTLIST book price CDATA "$100">
   7 <!ATTLIST book author CDATA "Herold">
   8 <!ATTLIST book number ID #REQUIRED>
   9 <!ATTLIST bookurn xmlns CDATA "10">
  10 <!ATTLIST bookurn xmlns:isbn CDATA "10">
  11 <!ENTITY w "William">
  12 <!ENTITY s "Shakespeare">