Appel, Kenneth I.,  1932- <br/><br/>
Every planar map is four colorable/ 
Kenneth Appel, and Wolfgang Haken. 
 - Providence, R.I.:  American Mathematical Society,  c1989. 
 - xv, 741 p.:  ill.;  25 cm. 
 - Contemporary mathematics,  v. 98.  0271-4132 ; .
 - Contemporary mathematics (American Mathematical Society);  v. 98. .
<br/><br/>Includes bibliographical references. 
<br/><br/><label>ISBN: </label>0821851039 (alk. paper) 
<br/><br/><label>LCCN: </label>89015011 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Four-color problem.<br/>Probleme des quatre couleurs.
<br/><br/><label>Dewey Class. No.: </label>511/.5