NOVIKOV, O. A.; RUKASOV, V. I. Approximation of classes of continuous functions by generalized de la Vallée-Poussin sums. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 8, p. 1069–1079, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5503. Acesso em: 5 dec. 2025.