<!-- The following DTD is a simple view of a book:
book
     index
        +
          word
               #PCDATA
          page
               #PCDATA
     chapter+
          comment?
               #PCDATA
          paragraph*
               #PCDATA
     summary?
          #PCDATA

     good
	EMPTY
-->

<!ENTITY % yesno 
    "(yes, no)"
>

<!ELEMENT summary (#PCDATA)>

<!ELEMENT book (summary?, chapter+, index+, available)>

<!ELEMENT available EMPTY>

<!ELEMENT index (word, ref+)>

<!ELEMENT ref (page, line)>

<!ELEMENT word (#PCDATA)>

<!ELEMENT line (#PCDATA)>

<!ELEMENT page (#PCDATA)>

<!ELEMENT chapter (comment?, paragraph*)>

<!ELEMENT paragraph (#PCDATA)>

<!ELEMENT comment (#PCDATA)>

<!ATTLIST book good %yesno; 'yes'>
<!ATTLIST summary length CDATA #REQUIRED>
<!ATTLIST summary lang CDATA #IMPLIED>
<!ATTLIST summary size CDATA #FIXED '12'>
<!ATTLIST chapter title CDATA #IMPLIED>
<!ATTLIST index color CDATA #IMPLIED>
<!ATTLIST index cross-ref %yesno; "no">
<!ATTLIST index glossary CDATA #FIXED "nope">
<!ATTLIST word freq CDATA #IMPLIED>