1<!DOCTYPE book [
2<!ELEMENT book (doc*)>
3<!ELEMENT doc (isid*)>
4<!ELEMENT isid EMPTY>
5<!ATTLIST isid myid ID #IMPLIED>
6]>
7<book>
8<doc>
9<isid myid="mine"/>
10<isid myid="dup"/>
11</doc>
12<!-- including another XML document with IDs -->
13<xinclude:include xmlns:xinclude="http://www.w3.org/2001/XInclude"
14		 href="../ents/ids.xml"/>
15</book>
16