Lestari RUI, Untari RS. Open Problem Based Learning (OPBL) Learning Model on Student Learning Outcomes in Operating System Lessons At Vocational High School: Model Pembelajaran Open Problem Based Learning (OPBL) Terhadap Hasil Belajar Siswa Pada Mata Pelajaran Sistem Operasi di SMK. acopen [Internet]. 2021 Oct. 21 [cited 2025 Sep. 3];4:10.21070/acopen.4.2021.3069. Available from: https://acopen.umsida.ac.id/index.php/acopen/article/view/3069