O. Ravi, M. Rajakalaivanan, and I. Rajasekaran. “Further Study of $\omega$-Closed Sets”. International Journal of Mathematics And its Applications 4, no. 1 - D (March 15, 2016): 67–72. Accessed May 19, 2024. http://ijmaa.in/index.php/ijmaa/article/view/618.