1<?xml version="1.0"?>
2<!DOCTYPE doc [
3<!ELEMENT doc (src | dest)*>
4<!ELEMENT src EMPTY>
5<!ELEMENT dest EMPTY>
6<!ATTLIST src ref IDREF #IMPLIED>
7<!ATTLIST dest id ID #IMPLIED>
8]>
9<doc>
10 <src ref="foo"/>
11 <dest id="foo"/>
12 <src ref="foo"/>
13</doc>
14