Ebrahim HH, Ahmed IS. On a New Kind of Collection of Subsets Noted by δ–field and Some Concepts Defined on δ–field. IHJPAS [Internet]. 2019 May 20 [cited 2024 Nov. 24];32(2):62-70. Available from: https://jih.uobaghdad.edu.iq/index.php/j/article/view/2140