%0 Journal Article
%A Fawcett, Barry
%T A Categorical Characterization of the Four Colour Theorem
%J Canadian mathematical bulletin
%D 1986
%P 426-431
%V 29
%N 4
%U http://geodesic.mathdoc.fr/articles/10.4153/CMB-1986-067-8/
%R 10.4153/CMB-1986-067-8
%F 10_4153_CMB_1986_067_8