<rss version="2.0" 
      xmlns:cf="http://www.microsoft.com/schemas/rss/core/2005" 
      xmlns:book="http://www.example.com/book"> 
  <channel> 
    <cf:treatAs>list</cf:treatAs> 
    <title>Books in My Collection</title> 
    <link>http://www.example.com/collectionofbooks.htm</link> 
    <description></description>
    <cf:listinfo> 
      <cf:sort label="Relevance" default="true" />
      <cf:sort ns="http://www.example.com/book"
        element="firstedition" label="First Edition" data-type="date" />
      <cf:sort
        element="title" label="Title" data-type="text" />
      <cf:group ns="http://www.example.com/book" element="genre" label="Genre" />
    </cf:listinfo>     
    <item>
      <title>Horror Stories, vol 16</title>
      <author>Steve</author>
      <description>Our favorite horror author provides us with another great collection</description>
      <book:firstedition>Thu, 25 Aug 2005 00:00:01 GMT</book:firstedition>
      <book:genre>Horror</book:genre>
    </item>
    <item>
      <title>Great Journeys of the Past</title>
      <author>Bob</author>
      <description>A wonderful history of great journeys</description>
      <book:firstedition>Sat, 07 Sep 2002 00:00:01 GMT</book:firstedition>
      <book:genre>Travel</book:genre>
    </item>
  </channel>
</rss>