%0 Journal Article %A V. M. Lebedeva %T The number of periodic solutions of a first order differential equation with right-hand side in the form of an incomplete polynomial %J Differencialʹnye uravneniâ %D 1969 %P 1029-1036 %V 5 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1969_5_6_a5/ %G ru %F DE_1969_5_6_a5