TY  - JOUR
AU  - N. P. Korneichuk
TI  - Extreme values of functionals and best approximation on classes of periodic functions
JO  - Izvestiya. Mathematics 
PY  - 1971
SP  - 97
EP  - 129
VL  - 5
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1971_5_1_a7/
LA  - en
ID  - IM2_1971_5_1_a7
ER  -