GAVRYLKIV, V.M. Superextensions of doppelsemigroups. Carpathian Mathematical Publications, [S. l.], v. 17, n. 2, p. 591–603, 2025. DOI: 10.15330/cmp.17.2.591-603. Disponível em: https://journals.pnu.edu.ua/index.php/cmp/article/view/8583. Acesso em: 11 jan. 2026.