Combinatorial Properties of Order Decreasing and Order Reversing  Partial One– to–One Transformation Semigroup. International Journal of Development Mathematics (IJDM), [S. l.], v. 3, n. 2, p. 090–098, 2026. DOI: 10.62054/ijdm/0302.06. Disponível em: https://ijdm.org.ng/index.php/Journals/article/view/343.. Acesso em: 27 jul. 2026.