NOVIKOV, O. A.; RUKASOV, V. I. Approximation of the classes $C_{β}^{ψ} H_{ω}$ by generalized de la Valiée-Poussin sums. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 4, p. 606–610, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5039. Acesso em: 5 dec. 2025.