%0 Journal Article
%A A. I. Fet
%T On a periodicity problem in the calculus of variations
%J Doklady Akademii Nauk
%D 1965
%P 287-289
%V 160
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1965_160_2_a9/
%G ru
%F DAN_1965_160_2_a9