%0 Journal Article
%A V. V. Velichenko
%T On sufficient conditions for optimality for multisheeted fields of extremals
%J Doklady Akademii Nauk
%D 1976
%P 757-760
%V 226
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1976_226_4_a3/
%G ru
%F DAN_1976_226_4_a3