@article{MZM_1999_65_6_a2,
     author = {M. G. Esmaganbetov},
     title = {Widths of classes from $L_2[0,2\pi]$ and the minimization of exact constants in {Jackson-type} inequalities},
     journal = {Matemati\v{c}eskie zametki},
     pages = {816--820},
     publisher = {mathdoc},
     volume = {65},
     number = {6},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1999_65_6_a2/}
}