<?xml version="1.0" encoding="UTF-8"?>
<!ELEMENT addressbook (person+)>
<!ELEMENT person (name,address,(fax | tel)*,email+)>
<!ELEMENT name 	((first,middle?,last) | (last,middle?,first))>
<!ELEMENT address (#PCDATA)>
<!ELEMENT last (#PCDATA)>
<!ELEMENT first (#PCDATA)>
<!ELEMENT middle (#PCDATA)>
<!ELEMENT tel (#PCDATA)>
<!ELEMENT fax (#PCDATA)>
<!ELEMENT email (#PCDATA)>