MANN’A, M. Q. Monoid and Topological Groupoid. The Journal of the Indian Mathematical Society, [S. l.], v. 85, n. 1-2, p. 192–201, 2018. DOI: 10.18311/jims/2018/15930. Disponível em: http://informaticsjournals.com/index.php/jims/article/view/15930. Acesso em: 2 may. 2024.