%0 Journal Article
%A D. S. Ushkho
%T On the number of singular points of the second group of a cubic system
%J Differencialʹnye uravneniâ
%D 1993
%P 240-245
%V 29
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1993_29_2_a6/
%G ru
%F DE_1993_29_2_a6