%0 Journal Article
%A E. E. Barbashina
%T Necessary conditions of Copa--Moir type for a Goursat--Darboux system
%J Differencialʹnye uravneniâ
%D 1989
%P 1045-1047
%V 25
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1989_25_6_a19/
%G ru
%F DE_1989_25_6_a19