Y. Y. Yousif, M.H. Jaber, and M. El Sayed. “Fibrewise Multi-Perfect Topological Spaces”. Ibn AL-Haitham Journal For Pure and Applied Sciences 36, no. 4 (October 20, 2023): 396–406. Accessed November 25, 2024. https://jih.uobaghdad.edu.iq/index.php/j/article/view/2911.