@article{IM2_2021_85_3_a9,
     author = {P. V. Paramonov},
     title = {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},
     journal = {Izvestiya. Mathematics},
     pages = {483--505},
     year = {2021},
     volume = {85},
     number = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2021_85_3_a9/}
}