%0 Journal Article
%A E. S. Pyatnitskii
%A L. B. Rapoport
%T A method for constructing invariant functions and the study of phase portraits of dynamical systems on a computer
%J Differencialʹnye uravneniâ
%D 1990
%P 1116-1126
%V 26
%N 7
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1990_26_7_a2/
%G ru
%F DE_1990_26_7_a2