DERECH, V. D. Structure of a permutable Munn semigroup of finite rank. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 6, p. 742–746, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3492. Acesso em: 11 apr. 2025.