%0 Journal Article
%A G. A. Yusupov
%T Best polynomial approximations and widths of certain classes of functions in the space~$L_2$
%J Eurasian mathematical journal
%D 2013
%P 120-126
%V 4
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/EMJ_2013_4_3_a9/
%G en
%F EMJ_2013_4_3_a9