%0 Journal Article %A I. M. Vul'pe %T Generalization of the averaging method of N. N. Bogolyubov to certain classes of differential equations without mean values %J Izvestiâ vysših učebnyh zavedenij. Matematika %D 1973 %P 28-32 %N 12 %U http://geodesic.mathdoc.fr/item/IVM_1973_12_a3/ %G ru %F IVM_1973_12_a3