@article{TRSPY_1987_180_a86,
     author = {A. K. Kushpel'},
     title = {Sharp estimates of the widths of convolution classes in the space $C_{2\pi}$},
     journal = {Informatics and Automation},
     pages = {148--149},
     publisher = {mathdoc},
     volume = {180},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TRSPY_1987_180_a86/}
}