Saaty, Thomas L. <br/><br/>
The four color problem  : assaults and conquest 

 - New York:  McGraw-Hill,  1977. 
 -  217p. 
<br/><br/> Includes index 
<br/><br/><br/>eng 
<br/><br/><label>ISBN: </label>0070543828 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Four color problem
<br/><br/><label>Dewey Class. No.: </label>514.22  / SAF