TY  - JOUR
AU  - O. A. Timoshin
TI  - Best approximation of partial differential operators
JO  - Matematičeskie zametki
PY  - 1989
SP  - 78
EP  - 87
VL  - 46
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MZM_1989_46_1_a8/
LA  - ru
ID  - MZM_1989_46_1_a8
ER  -