Fritsch, Rudolf <br/><br/>
The four-color theorem  history, topological foundations, and idea of proof 

 - New York  Springer  1994 
 - xvi,260p.  24cm 
<br/><br/><label>ISBN: </label>0387984976 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Graph theory
<br/><br/><label>Dewey Class. No.: </label>511.5  / FRI