@article{MZM_1981_29_5_a9,
     author = {A. N. Davidchik and A. A. Ligun},
     title = {Precise constants in inequalities of {Jackson} type},
     journal = {Matemati\v{c}eskie zametki},
     pages = {761--769},
     publisher = {mathdoc},
     volume = {29},
     number = {5},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1981_29_5_a9/}
}