RUKASOV, V. I.; CHAICHENKO, S. O. Approximation by de la Vallée-Poussin operators on the classes of functions locally summable on the real axis. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 7, p. 968–978, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2929. Acesso em: 6 dec. 2025.