O. Ravi, I. Rajasekaran, S. Murugesan, and A. Pandi. “On $\beta$-Normal Spaces”. International Journal of Mathematics And its Applications 3, no. 2 (June 15, 2015): 35–44. Accessed July 3, 2024. https://ijmaa.in/index.php/ijmaa/article/view/418.