NESTERENKO, A. N.; PETROVA, T. O. On one problem for comonotone approximation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 57, n. 10, p. 1424–1429, 2005. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3697. Acesso em: 6 dec. 2025.