%0 Journal Article
%A A. A. Andronov
%A E. A. Leontovich
%T Sufficient conditions for the ``structural instability of the first degree'' of a dynamical system on the plane
%J Differencialʹnye uravneniâ
%D 1970
%P 2121-2134
%V 6
%N 12
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1970_6_12_a1/
%G ru
%F DE_1970_6_12_a1