TY  - GEN
AU  - Ore,Oystein
TI  - The four�olor problem
T2  - Pure and applied mathematics; a series of monographs and textbooks
AV  - QA3 .P8 no. 27
U1  - 513.83 
PY  - 1967///
CY  - New York
PB  - Academic Press, 
KW  - Applied mathematics
KW  - Four�olor problem
N1  - Includes bibliography & indexes
ER  -