%0 Journal Article
%A Solomon Lefschetz
%T Complete families of periodic solutions of differential equations.
%J Commentarii mathematici Helvetici
%D 1954
%P 341-345
%V 28
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMH_1954__28_139089/
%F CMH_1954__28_139089