<?xml version="1.0"?>
<!DOCTYPE address 
[
   <!ELEMENT address (buildingnumber, street, city, state, zip)>
   <!ATTLIST address xmlns CDATA #IMPLIED>
   <!ELEMENT buildingnumber (#PCDATA)>
   <!ELEMENT street (#PCDATA)>
   <!ELEMENT city (#PCDATA)>
   <!ELEMENT state (#PCDATA)>
   <!ELEMENT zip (#PCDATA)>
]>

<address>
  <buildingnumber> 29 </buildingnumber>
  <street> South Lasalle Street</street>
  <city>Chicago</city>
  <state>Illinois</state>
  <zip>60603</zip>
</address>
