@article{MZM_1992_51_6_a15,
     author = {V. T. Shevaldin},
     title = {Widths of classes of convolutions with {Poisson} kernel},
     journal = {Matemati\v{c}eskie zametki},
     pages = {126--136},
     year = {1992},
     volume = {51},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1992_51_6_a15/}
}