Labendia, Mhelmar, and Laika Angela Añora. “Theta_beta-Open Sets and theta_beta-Continuous Functions in the Product Space”. The Mindanawan Journal of Mathematics 7, no. 1 (May 31, 2025): 69–85. Accessed August 23, 2025. https://journals.msuiit.edu.ph/tmjm/article/view/793.