%0 Journal Article
%A F. H. Szafraniec
%T Note on the existence of periodic solutions of a second order differential equation
%J Annales Polonici Mathematici
%D 1968
%P 305-307
%V 21
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/ap-21-3-305-307/
%R 10.4064/ap-21-3-305-307
%G en
%F 10_4064_ap_21_3_305_307