<?xml version="1.0" encoding="UTF-8"?>
-<book xml:id="simple_book" xmlns="http://docbook.org/ns/docbook">
+<book xmlns="http://docbook.org/ns/docbook">
<title>Very simple book</title>
- <chapter xml:id="chapter_1">
+ <chapter>
<title>Chapter 1</title>
<para>Hello world!</para>
<para>I hope that your day is proceeding <emphasis>splendidly</emphasis>!</para>
</chapter>
- <chapter xml:id="chapter_2">
+ <chapter>
<title>Chapter 2</title>
<para>Hello again, world!</para>
</chapter>