Item 9: Distinguish text from markup
¥A DocBook element
¥<programlisting><![CDATA[<value>
  <double>28657</double>
</value>]]></programlisting>
¥The content is:
<value>
  <double>28657</double>
</value>
¥This is the same:
<programlisting>&lt;value&gt;
  &lt;double&gt;28657&lt;/double&gt;
 &lt;/value&gt;</programlisting>