Fritsch, Rudolf <br/><br/>
The Four-color theorem :  History, topological foundations and idea of proof / 
Rudolf Fritsch and Gerda Fritsch 
 - New York  Springer-Verlag  1998 
 - xvi, 260p 
<br/><br/><label>ISBN: </label>9780387984971 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Mathematics<br/>Four-color problem
<br/><br/><label>Dewey Class. No.: </label>511.5  / FRI