<!-- Target DTD for combining data from multiple bookstores. -->

<!ELEMENT combined (store*)>
<!ELEMENT store (book*)>

<!-- The name of the bookstore -->
<!ATTLIST store
      name   CDATA  #REQUIRED>

<!ELEMENT book (title, author+, category, publisher, price+)>
<!ATTLIST book
      isbn CDATA    #REQUIRED
      status (InStock | SpecialOrder) #IMPLIED >

<!-- The title of the book -->
<!ELEMENT title (#PCDATA)>

<!-- Each author has a first name (fname) and last name (lname) -->
<!ELEMENT author (fname, lname)>
<!ELEMENT fname (#PCDATA)>
<!ELEMENT lname (#PCDATA)>
      
<!-- The kind of book, e.g., Science Fiction, History, Childrens, etc. -->
<!ELEMENT category (#PCDATA)>

<!-- The name of the publisher -->
<!ELEMENT publisher (#PCDATA)>

<!-- The price consists of a currency and amount. The currency codes
are USD for U.S. dollar, CAD for Canadian dollar, and EUR for Euro.  -->
<!ELEMENT price EMPTY>
<!ATTLIST price
      currency (USD | CAD | EUR) #REQUIRED 
      amount   CDATA           #REQUIRED>