%0 Journal Article
%A V. S. Mel'nik
%T Extremal problems for operator-differential systems
%J Doklady Akademii Nauk
%D 1990
%P 101-105
%V 314
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1990_314_1_a23/
%G ru
%F DAN_1990_314_1_a23