@article{IM2_1997_61_2_a5,
     author = {S. N. Kudryavtsev},
     title = {Approximating one class of finitely differentiable functions by another},
     journal = {Izvestiya. Mathematics },
     pages = {347--362},
     publisher = {mathdoc},
     volume = {61},
     number = {2},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_2_a5/}
}