%0 Journal Article
%A N. G. Makeev
%T A~differential equation that determines the Poincaré function in a~neighborhood of a~focus
%J Izvestiâ vysših učebnyh zavedenij. Matematika
%D 1990
%P 55-62
%N 12
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IVM_1990_12_a7/
%G ru
%F IVM_1990_12_a7