Sect1 -- A top-level section of document. Sect1 reference.

  <sect1>
    <title>sect1 tag</title>
    <para>
      Sect1 -- A top-level section of document.
      <ulink url="http://www.oasis-open.org/docbook/documentation/reference/html/sect1.html">Sect1 reference</ulink>.
    </para>

    <sect2>
      <title>sect2 tag</title>
      <para>
	Sect2 -- A subsection within a Sect1.
	<ulink url="http://www.oasis-open.org/docbook/documentation/reference/html/sect2.html">Sect2 reference</ulink>.
      </para>
      <sect3>
	<title>tag: sect3</title>
	<para>
	  Sect3 -- A subsection within a Sect2.
	  <ulink url="http://www.oasis-open.org/docbook/documentation/reference/html/sect2.html">Sect3 reference</ulink>.
	  Do you want to know more about sect4 ?
	</para>
      </sect3>
      <sect3>
	<title>plop again sect3</title>
	<para>
	  data for section 3.
	</para>
      </sect3>
    </sect2>
  </sect1>