ZELINSKII, Yu. B. Multiplicity of Continuous Mappings of Domains. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 57, n. 4, p. 554–558, 2005. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3620. Acesso em: 5 dec. 2025.