TY - JOUR AU - N. K. Bari TI - On locally best approximation of periodic functions by trigonometric polynomials JO - Uchenye Zapiski Moskovskogo Gosudarstvennogo Universiteta PY - 1956 SP - 107 EP - 138 VL - 181 IS - 181 UR - http://geodesic.mathdoc.fr/item/UZMU_1956_181_181_a8/ LA - ru ID - UZMU_1956_181_181_a8 ER -