<!DOCTYPE doc [<!ELEMENT doc (src | dest)*><!ELEMENT src EMPTY><!ELEMENT dest EMPTY><!ATTLIST src ref IDREF #IMPLIED><!ATTLIST dest id ID #IMPLIED>]><doc> <src ref="foo"/> <dest id="foo"/> <src ref="foo"/></doc> <!DOCTYPE doc [
<!ELEMENT doc (src | dest)*>
<!ELEMENT src EMPTY>
<!ELEMENT dest EMPTY>
<!ATTLIST src ref IDREF #IMPLIED>
<!ATTLIST dest id ID #IMPLIED>
]>
<doc>
<src ref="foo"/>
<dest id="foo"/>
<src ref="foo"/>
</doc>