<?xml version="1.0"?>
 <!-- initially, the default namespace is "books" -->
 <book xmlns='urn:loc.gov:books'
       xmlns:isbn='urn:ISBN:0-395-36341-6'
       xmlns:fcat='http://FourThought.com/catalog'>
     <title>Cheaper by the Dozen</title>
     <isbn:number>1568491379</isbn:number>
     <notes fcat:ref='ITEM54321'>
       <!-- make HTML the default namespace for some commentary -->
       <p xmlns='urn:w3-org-ns:HTML'>
           This is a <i>funny</i> book!
       </p>
     </notes>
 </book>
