@article{MZM_1985_38_2_a8,
     author = {A. A. Ligun},
     title = {Exact constants in inequalities of {Jackson} type},
     journal = {Matemati\v{c}eskie zametki},
     pages = {248--256},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1985_38_2_a8/}
}