A. Devika, and P. Perianayaki. “On **$b$-$t$**-Sets and **$b$-**$t$-Sets in Topological Spaces”. International Journal of Mathematics And Its Applications, vol. 4, no. 1 - A, Jan. 2016, pp. 69-79, http://ijmaa.in/index.php/ijmaa/article/view/547.