GENCHEV, T. On the investigations of Nikola Obreshkoff connected with the regularly monotonic functions (in Bulgarian, summary in English). Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 89, p. 23–35, 1997. Disponível em: https://ftl5.uni-sofia.bg/index.php/fmi/article/view/352. Acesso em: 22 nov. 2024.