Ore, Oystein,  1899-1968. <br/><br/>
The four�olor problem / 
Oystein Ore. 
 - New York :  Academic Press,   c1967. 
 - xv, 259 p. :  ill. ;  24 cm. 
 - Pure and applied mathematics; a series of monographs and textbooks ;  27 .
<br/><br/>Includes bibliography & indexes. 
<br/><br/><label>LCCN: </label>66030095  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Applied mathematics.<br/>Four�olor problem.
<br/><br/><label>LC Class. No.: </label>QA3  / .P8 no. 27 
<br/><br/><label>Dewey Class. No.: </label>513.83  / ORE