%0 Journal Article
%A N. I. Vulpe
%A I. V. Nikolaev
%T Topological classification of a quadratic system with a four-fold singular point
%J Differencialʹnye uravneniâ
%D 1993
%P 1669-1674
%V 29
%N 10
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1993_29_10_a1/
%G ru
%F DE_1993_29_10_a1