STEPANETS, O. I. Approximation of $\bar {\psi} - \text{Integrals}$ of periodic functions by Fourier sums (small smoothness). IIof periodic functions by Fourier sums (small smoothness). II. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 3, p. 388–400, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4938. Acesso em: 5 dec. 2025.