%0 Journal Article
%A K. B. Sabitov
%T The maximum principle for systems of second-order equations of mixed type
%J Differencialʹnye uravneniâ
%D 1990
%P 488-494
%V 26
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1990_26_3_a16/
%G ru
%F DE_1990_26_3_a16