%0 Journal Article
%A S. Yu. Yakovenko
%T On the concept of an infinite extremal in stationary problems of
%J Doklady Akademii Nauk
%D 1989
%P 798-802
%V 308
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1989_308_4_a6/
%G ru
%F DAN_1989_308_4_a6