<!ELEMENT foo (string|enum)+>
<!ELEMENT string EMPTY>
<!ELEMENT enum EMPTY>
<!ATTLIST string
        att1   CDATA    #IMPLIED
        att2   CDATA    #REQUIRED
        att3   CDATA    #FIXED "POST"
        att4   CDATA    "mydefault">
<!ATTLIST enum
        en1   (bullets|ordered|glossary)  "ordered"
        en2   (pkg|ext|php|prog|ldlib)    #REQUIRED
        en3   (has|eq|lt|le|gt|ge)        #IMPLIED>
<!ATTLIST unsupported
        att1   ID       #IMPLIED
        att2   IDREF    #IMPLIED
        att3   IDREFS   #IMPLIED
        att4   NMTOKEN  #IMPLIED
        att5   NMTOKENS #IMPLIED>
<!ATTLIST notdeclared
        not    CDATA    #IMPLIED>