%0 Journal Article
%A Le Khyu Zien
%A V. I. Shevchenko
%T Homotopy classification of Petrovskii elliptic systems of equations in the plane
%J Doklady Akademii Nauk
%D 1978
%P 26-28
%V 238
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1978_238_1_a4/
%G ru
%F DAN_1978_238_1_a4