%0 Journal Article
%A A. F. Filippov
%T The infinitesimal order of perturbations preserving the instability of a singular point
%J Differencialʹnye uravneniâ
%D 2000
%P 1037-1044
%V 36
%N 8
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_2000_36_8_a3/
%G ru
%F DE_2000_36_8_a3