%0 Journal Article %A S. M. Nikol'skii %T Approximations of periodic functions by trigonometrical polynomials %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1945 %P 3-76 %V 15 %I mathdoc %U http://geodesic.mathdoc.fr/item/TM_1945_15_a0/ %G ru %F TM_1945_15_a0