%0 Journal Article %A A. Ya. Lepin %T Necessary and sufficient conditions for the existence of a solution of the two-point boundary value problem for a second order nonlinear ordinary differential equation %J Differencialʹnye uravneniâ %D 1970 %P 1384-1388 %V 6 %N 8 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1970_6_8_a5/ %G ru %F DE_1970_6_8_a5