<!ELEMENT poem ( title, author, stanza* )>
	<!ELEMENT title (#PCDATA) >
	<!ELEMENT author (firstname, lastname) >
	<!ELEMENT firstname (#PCDATA) >
	<!ELEMENT lastname (#PCDATA) >
	<!ELEMENT stanza (line+ | linein+) >
	<!ELEMENT line (#PCDATA) >
	<!ELEMENT linein (#PCDATA) >