The approximation of certain classes of differentiable periodic functions of two variables by Fourier sums
English version (Springer): Ukrainian Mathematical Journal 25 (1973), no. 5, pp 498-506.
Citation Example: Stepanets O. I. The approximation of certain classes of differentiable periodic functions of two variables by Fourier sums // Ukr. Mat. Zh. - 1973. - 25, № 5. - pp. 599—609.
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