%0 Journal Article %A A. M. Filimonov %T Periodic solutions of certain nonlinear partial differential equations %J Differencialʹnye uravneniâ %D 1976 %P 2076-2084 %V 12 %N 11 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1976_12_11_a19/ %G ru %F DE_1976_12_11_a19