%0 Journal Article %A P. E. Sobolevskii %T A certain type of differential equations in a Banach space %J Differencialʹnye uravneniâ %D 1968 %P 2278-2280 %V 4 %N 12 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1968_4_12_a12/ %G ru %F DE_1968_4_12_a12