TY  - JOUR
TI  - The four-color problem, by Oystein Ore. Academic Press, New York, 1967. xv + 259 pages. $12.00.
JO  - Canadian mathematical bulletin
PY  - 1968
SP  - 161
EP  - 163
VL  - 11
IS  - 1
UR  - http://geodesic.mathdoc.fr/articles/10.1017/S0008439500028915/
DO  - 10.1017/S0008439500028915
ID  - 10_1017_S0008439500028915
ER  -