TY  - JOUR
AU  - N. P. Korneichuk
TI  - Inequalities for differentiable periodic functions and best approximation of one class of functions by another
JO  - Izvestiya. Mathematics 
PY  - 1972
SP  - 417
EP  - 428
VL  - 6
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1972_6_2_a5/
LA  - en
ID  - IM2_1972_6_2_a5
ER  -