Taha H. Jasim, Ali A. Shihab, and Shaymaa A. Hameed. “Anew Types of Contra Continuity in Bi-Supra Topological Space”. Tikrit Journal of Pure Science 20, no. 4 (February 10, 2023): 170–176. Accessed June 18, 2025. https://tjpsj.org/index.php/tjps/article/view/1232.