P. SREENIVASULU REDDY. Structure of Regular Semigroups. Global Journal of Science Frontier Research, [S. l.], v. 15, n. F3, p. 1–8, 2015. Disponível em: https://journalofscience.org/index.php/GJSFR/article/view/1539. Acesso em: 4 may. 2024.