@article{SM_1992_71_1_a11,
     author = {P. V. Paramonov},
     title = {On harmonic approximation in the $C^1$-norm},
     journal = {Sbornik. Mathematics},
     pages = {183--207},
     publisher = {mathdoc},
     volume = {71},
     number = {1},
     year = {1992},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1992_71_1_a11/}
}