@article{MZM_1972_12_5_a2,
     author = {N. P. Korneichuk},
     title = {A note on {Jackson's} theorem for differentiable functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {517--522},
     publisher = {mathdoc},
     volume = {12},
     number = {5},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1972_12_5_a2/}
}