<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE book [
  <!ELEMENT book (quantity,(paperback|hardback),shelving)>
  <!ATTLIST book title CDATA #REQUIRED >
  <!ATTLIST book author CDATA #REQUIRED >
  <!ELEMENT quantity (#PCDATA)>
  <!ELEMENT shelving (shelve+)>
  <!ELEMENT shelve (#PCDATA)>
  <!ELEMENT paperback EMPTY>
  <!ELEMENT hardback EMPTY>
  ]>

<book title="Java Network Programming Black Book" author="Al Williams">
    <quantity>10</quantity>
    <paperback/>
    <shelving>
      <shelve>Computer</shelve>
      <shelve>Java</shelve>
      <shelve>Programming</shelve>
    </shelving>
</book>
