%0 Journal Article
%A P. P. Korovkin
%T An extermal problem and linear methods of summation of Fourier series
%J Doklady Akademii Nauk
%D 1967
%P 265-267
%V 177
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1967_177_2_a3/
%G ru
%F DAN_1967_177_2_a3