@article{MZM_2010_87_4_a12,
     author = {M. Sh. Shabozov},
     title = {Widths of {Classes} of {Periodic} {Differentiable} {Functions} in the {Space~}$L_{2}[0,2\pi]$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {616--623},
     publisher = {mathdoc},
     volume = {87},
     number = {4},
     year = {2010},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2010_87_4_a12/}
}