SHARA, J. On Free ɼ-Semigroups. International Journal For Research In Mathematics And Statistics, [S. l.], v. 3, n. 5, p. 15–28, 2017. DOI: 10.53555/ms.v3i5.229. Disponível em: https://gnpublication.org/index.php/ms/article/view/229. Acesso em: 4 may. 2024.