Lellis Thivagar, M., S. Athisaya Ponmani, R. Raja Rajeswari, and E. Ekici. “On Some Bitopological 𝛾-Separation Axioms”. CUBO, A Mathematical Journal, vol. 10, no. 3, Oct. 2008, pp. 137–144, https://cubo.ufro.cl/ojs/index.php/cubo/article/view/1506.