@article{IM2_1994_42_2_a3,
     author = {P. V. Paramonov},
     title = {On~approximation by harmonic polynomials in the $C^1$-norm on compact sets in~$\mathbf R^2$},
     journal = {Izvestiya. Mathematics},
     pages = {321--331},
     year = {1994},
     volume = {42},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1994_42_2_a3/}
}