Attribute Declarations

  <?xml version="1.0"?>
  <!DOCTYPE exam [
    <!ELEMENT exam (qapair)*>
    <!ATTLIST exam author CDATA #REQUIRED>
    <!ATTLIST exam paper CDATA #REQUIRED>
    <!ELEMENT qapair (question,answer)>
    <!ATTLIST qapair number CDATA #REQUIRED>
    <!ELEMENT question (#PCDATA)>
    <!ELEMENT answer (#PCDATA)>
  ]>