ZELINSKII, Yu. B.; KLISHCHUK, B. A.; TKACHUK, M. V. Theorems on Inclusion for Multivalued Mappings. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 66, n. 7, p. 1003–1005, 2014. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2194. Acesso em: 6 dec. 2025.