%0 Journal Article
%A I. A. Muzychuk
%T Nonexistence of some twelfth-order $4$-critical graphs
%J Vestnik Moskovskogo universiteta. Matematika, mehanika
%D 1989
%P 58-60
%N 6
%U http://geodesic.mathdoc.fr/item/VMUMM_1989_6_a14/
%G ru
%F VMUMM_1989_6_a14