TY  - JOUR
AU  - G. A. Yusupov
TI  - Best polynomial approximations and widths of certain classes of functions in the space~$L_2$
JO  - Eurasian mathematical journal
PY  - 2013
SP  - 120
EP  - 126
VL  - 4
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/EMJ_2013_4_3_a9/
LA  - en
ID  - EMJ_2013_4_3_a9
ER  -