%0 Journal Article %A Hedetniemi, Stephen %T On Partitioning Planar Graphs %J Canadian mathematical bulletin %D 1968 %P 203-211 %V 11 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-1968-023-5/ %R 10.4153/CMB-1968-023-5 %F 10_4153_CMB_1968_023_5