%0 Journal Article
%A A. A. Iosif'yan
%T Characteristic problems with a principal part that contains mixed derivatives
%J Differencialʹnye uravneniâ
%D 1976
%P 309-324
%V 12
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1976_12_2_a14/
%G ru
%F DE_1976_12_2_a14