NovikovO. A., and RukasovV. I. “Approximation of the Classes $C_{β}^{ψ} H_{ω}$ by Generalized De La Valiée-Poussin Sums”. Ukrains’kyi Matematychnyi Zhurnal 49, no. 4 (April 25, 1997): 606-610. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5039.