DEMKIV, I. I.; MAKAROV, V. L. Approximation of Urysohn operator with operator polynomials of Stancu type. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 64, n. 3, p. 318–343, 2012. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2579. Acesso em: 5 dec. 2025.