O. Ravi, S. Padmasekaran, S. Usharani, and I. Rajasekaran. “$\breve{g}$-Closed and $\breve{g}$-Open Maps in Topological Spaces”. International Journal of Mathematics And Its Applications, vol. 3, no. 4 - C, Dec. 2015, pp. 1-8, http://ijmaa.in/index.php/ijmaa/article/view/500.