RUKASOV , V. I. Approximation of the functions preset on the real axis by the Valle Pussen operators . Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 5, p. 682–691, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/7965. Acesso em: 6 dec. 2025.