%0 Journal Article
%A Tutte, W. T.
%T Chromatic Sums for Rooted Planar Triangulations: The Cases λ = 1 and λ = 2
%J Canadian journal of mathematics
%D 1973
%P 426-447
%V 25
%N 2
%U http://geodesic.mathdoc.fr/articles/10.4153/CJM-1973-043-3/
%R 10.4153/CJM-1973-043-3
%F 10_4153_CJM_1973_043_3