%0 Journal Article %A V. Kh. Froim %T A system of equations that are degenerate on the plane %J Differencialʹnye uravneniâ %D 1977 %P 1218-1224 %V 13 %N 7 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1977_13_7_a7/ %G ru %F DE_1977_13_7_a7