@article{MZM_1971_9_2_a0,
     author = {V. V. Arestov and V. N. Gabushin},
     title = {Approximation of classes of differentiable functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {105--112},
     year = {1971},
     volume = {9},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1971_9_2_a0/}
}