ZUBAIRU, M. M. On the subsemigroup generated by idempotents of the semigroup of order preserving and decreasing contraction mappings of a finite chain: On the subsemigroup generated by idempotents. Journal of the Nigerian Mathematical Society, [S. l.], v. 42, n. 2, p. 140–152, 2023. Disponível em: https://ojs.ictp.it/jnms/index.php/jnms/article/view/934. Acesso em: 13 sep. 2024.