@article{SM_2020_211_8_a3,
     author = {P. V. Paramonov and K. Yu. Fedorovskiy},
     title = {On $C^m$-reflection of harmonic functions and $C^m$-approximation by harmonic polynomials},
     journal = {Sbornik. Mathematics},
     pages = {1159--1170},
     year = {2020},
     volume = {211},
     number = {8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2020_211_8_a3/}
}