Finished DTD

<!ENTITY % xhtml1 SYSTEM "http://www.w3.org/TR/xhtml1/DTD/strict.dtd">
%xhtml1;

<!ELEMENT category (#PCDATA)>
<!ELEMENT abstract (#PCDATA)>
<!ELEMENT keyword (#PCDATA)>
<!ELEMENT last_updated (#PCDATA)>

<!-- e.g. "1999 New York Women Composers", 
     not "Copyright 1999 New York Women Composers" -->
<!ELEMENT copyright (#PCDATA)>


<!ELEMENT instruments (#PCDATA)>
<!ELEMENT publisher (#PCDATA)>
<!ELEMENT length (#PCDATA)>

<!ELEMENT date (year | ISODate)>
<!ELEMENT year (#PCDATA)>
<!ELEMENT ISODate (#PCDATA)>

<!ELEMENT catalog (category, cataloging_info, last_updated, 
   copyright, maintainer, (composer | composition)*)>

<!ELEMENT cataloging_info (abstract, keyword+)>

<!ELEMENT description %Block;>

<!ELEMENT maintainer (name)>
<!ELEMENT name (first_name, middle_name, last_name)>
<!ELEMENT first_name (#PCDATA)>
<!ELEMENT middle_name (#PCDATA)>
<!ELEMENT last_name (#PCDATA)>
<!ATTLIST maintainer email CDATA #REQUIRED 
                     url   CDATA #IMPLIED>
                     
<!ELEMENT composer (name)>
<!ATTLIST composer id ID #REQUIRED>

<!ELEMENT composition (title, date, length?, instruments, description?, publisher?)>
<!ATTLIST composition composer IDREFS #REQUIRED>

<!ATTLIST a href CDATA #IMPLIED>