GAVRYLKIV, V.M. On representation of semigroups of inclusion hyperspaces. Carpathian Mathematical Publications, [S. l.], v. 2, n. 1, p. 24–34, 2010. Disponível em: https://ktipe.pnu.edu.ua/index.php/cmp/article/view/3990. Acesso em: 16 may. 2025.