TY  - JOUR
AU  - P. V. Paramonov
TI  - Criteria for $C^1$-approximability of functions on compact sets in~${\mathbb{R}}^N$, $N\geqslant 3$, by solutions of~second-order homogeneous elliptic equations
JO  - Izvestiya. Mathematics 
PY  - 2021
SP  - 483
EP  - 505
VL  - 85
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_2021_85_3_a9/
LA  - en
ID  - IM2_2021_85_3_a9
ER  -