EBRAHIM, Hassan H.; AHMED, Ibrahim S. On a New Kind of Collection of Subsets Noted by δ–field and Some Concepts Defined on δ–field. Ibn AL-Haitham Journal For Pure and Applied Sciences, Baghdad, Iraq., v. 32, n. 2, p. 62–70, 2019. DOI: 10.30526/32.2.2140. Disponível em: https://jih.uobaghdad.edu.iq/index.php/j/article/view/2140. Acesso em: 31 mar. 2025.