Amin, Saiful, Sumarmi Sumarmi, Syamsul Bachri, Singgih Susilo, and Abdul Bashith. “The Effect of Problem-Based Hybrid Learning (PBHL) Models on Spatial Thinking Ability and Geography Learning Outcomes”. International Journal of Emerging Technologies in Learning (iJET) 15, no. 19 (October 5, 2020): pp. 83–94. Accessed May 1, 2024. https://online-journals.org/index.php/i-jet/article/view/15729.