TY  - JOUR
AU  - È. M. Saak
TI  - Approximation theorems for differential equations
JO  - Doklady Akademii Nauk
PY  - 1965
SP  - 1249
EP  - 1252
VL  - 165
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1965_165_6_a7/
LA  - ru
ID  - DAN_1965_165_6_a7
ER  -