TY  - JOUR
AU  - O. A. Timoshin
TI  - Order of the best approximation of partial differential operators
JO  - Matematičeskie zametki
PY  - 1990
SP  - 115
EP  - 121
VL  - 48
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1990_48_4_a12/
LA  - ru
ID  - MZM_1990_48_4_a12
ER  -