TY - JOUR AU - A. K. Kushpel' TI - Sharp estimates of the widths of convolution classes in the space $C_{2\pi}$ JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1987 SP - 148 EP - 149 VL - 180 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1987_180_a86/ LA - ru ID - TM_1987_180_a86 ER -