TY  - JOUR
AU  - V. I. Berdyshev
TI  - Best approximations in $L_[0,infty)$ of the differentiation operator
JO  - Matematičeskie zametki
PY  - 1971
SP  - 477
EP  - 481
VL  - 9
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1971_9_5_a0/
LA  - ru
ID  - MZM_1971_9_5_a0
ER  -