RUKASOV, V. I.; SILIN, E. S. Approximation of Continuous Functions of Low Smoothness by de la Vallee-Poussin Operators. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 57, n. 3, p. 394–399, 2005. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3607. Acesso em: 6 dec. 2025.