<!ELEMENT geography (state|city)*>
<!ELEMENT state (scode, sname, capital, citiesin*, nickname, population)>
  <!ATTLIST state id ID #REQUIRED>
<!ELEMENT scode (#PCDATA)>
<!ELEMENT sname (#PCDATA)>
<!ELEMENT capital EMPTY>
  <!ATTLIST capital idref IDREF #REQUIRED>
<!ELEMENT citiesin EMPTY>
  <!ATTLIST citiesin idref IDREF #REQUIRED>
<!ELEMENT nickname (#PCDATA)>
<!ELEMENT population (#PCDATA)>
<!ELEMENT city (ccode, cname, stateof)>
  <!ATTLIST city id ID #IMPLIED>
<!ELEMENT ccode (#PCDATA)>
<!ELEMENT cname (#PCDATA)>
<!ELEMENT stateof EMPTY>
  <!ATTLIST stateof idref IDREF #REQUIRED>