<billing.information person.href='person.1.xml'> 
  <credit.card id='c1' type='visa' number='1234123412341234' expires.on='20000601'>
    <name>Jane Smith</name> 
    <us.address object.id='object:account2:0007'> 
      <street>10 Saturn Terrace</street> 
      <city>New York</city> 
      <state>NY</state>
      <zip main='10001' sub='1000'/> 
    </us.address> 
  </credit.card> 
</billing.information>