On the maximal planar graphs and the four colour problem
1954 ◽
Vol 6
◽
pp. 80-91
◽
Keyword(s):
2019 ◽
Vol E102.A
(9)
◽
pp. 994-1001
2019 ◽
Vol E102.A
(9)
◽
pp. 1007-1016
◽
Keyword(s):
Keyword(s):
1996 ◽
Vol 39
(2)
◽
pp. 378-386
◽