TY  - JOUR
AU  - V. N. Gabushin
TI  - On the best approximation of the differentiation operator on the half-line
JO  - Matematičeskie zametki
PY  - 1969
SP  - 573
EP  - 582
VL  - 6
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1969_6_5_a7/
LA  - ru
ID  - MZM_1969_6_5_a7
ER  -