%0 Journal Article
%A L. A. Cherkas
%A I. L. Shevtsov
%T Normal-Size Limit Cycles of Quadratic Systems with a Structurally Unstable Focus
%J Differencialʹnye uravneniâ
%D 2004
%P 1076-1084
%V 40
%N 8
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_2004_40_8_a7/
%G ru
%F DE_2004_40_8_a7