%0 Journal Article
%A V. N. Gabushin
%T On the best approximation of the differentiation operator on the half-line
%J Matematičeskie zametki
%D 1969
%P 573-582
%V 6
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1969_6_5_a7/
%G ru
%F MZM_1969_6_5_a7