%0 Journal Article
%A B. M. Budak
%A E. M. Berkovich
%T The approximation of extremal problems
%J Doklady Akademii Nauk
%D 1970
%P 959-962
%V 192
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1970_192_5_a0/
%G ru
%F DAN_1970_192_5_a0