Ali, Rasha, and Noori F. Al-Mayahi. “λ - Borel and λ - Baire Credibility on Normal Topological Space”. Al-Qadisiyah Journal of Pure Science 26, no. 3 (June 20, 2021): Math. 23-. Accessed December 2, 2025. https://journalsc.qu.edu.iq/index.php/JOPS/article/view/1309.