XML DocBook II.

Example 1. Master document

<?xml version="1.0" encoding="iso-8859-2"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" 
                      "http://www.oasis-open.org/docbook/xml/4.0/docbookx.dtd" [
<!ENTITY chapter1 SYSTEM "chapter1.xml">
<!ENTITY chapter2 SYSTEM "chapter2.xml">
]>
<book>
  <title>Sample Book</title>
  &chapter1;
  &chapter2;
</book>

Example 2. External entity

<?xml encoding="iso-8859-2"?>
<chapter>
  <title>Sample chapter</title>
  ...
</chapter>