%0 Journal Article
%A Yu. S. Ilyashenko
%T The origin of limit cycles under perturbation of the equation $\dfrac{dw}{dz}=-\dfrac{R_z}{R_w}$, where $R(z,w)$ is a~polynomial
%J Sbornik. Mathematics
%D 1969
%P 353-364
%V 7
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1969_7_3_a4/
%G en
%F SM_1969_7_3_a4