%0 Journal Article %A Yu. N. Bibikov %T The existence of conditionally periodic solutions of systems of differential equations %J Differencialʹnye uravneniâ %D 1971 %P 1347-1356 %V 7 %N 8 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1971_7_8_a0/ %G ru %F DE_1971_7_8_a0