ILMURADOV, D. D. On differential properties of real functions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 7, p. 842–848, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5675. Acesso em: 5 dec. 2025.