Lestari, Rifkah Umami Indah, and Rahmania Sri Untari. 2021. “Open Problem Based Learning (OPBL) Learning Model on Student Learning Outcomes in Operating System Lessons At Vocational High School”. Academia Open 4 (October), 10.21070/acopen.4.2021.3069. https://doi.org/10.21070/acopen.4.2021.3069.