TY - JOUR AU - A. N. Davidchik AU - A. A. Ligun TI - Approximation of periodic functions by linear operators JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1987 SP - 98 EP - 99 VL - 180 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1987_180_a53/ LA - ru ID - TM_1987_180_a53 ER -