TY - JOUR AU - V. A. Klyachin TI - Approximation of the gradient of a~function on the basis of a~special JO - Izvestiya. Mathematics PY - 2018 SP - 1136 EP - 1147 VL - 82 IS - 6 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/IM2_2018_82_6_a2/ LA - en ID - IM2_2018_82_6_a2 ER -