%0 Journal Article %A Mehri, B. %T A note on periodic solution of second order non-linear differential equations %J Archivum mathematicum %D 1977 %P 191-194 %V 13 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/ARM_1977__13_4_a2/ %G en %F ARM_1977__13_4_a2