Lestari, R. U. I., and R. S. Untari. “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”. Academia Open, vol. 4, Oct. 2021, p. 10.21070/acopen.4.2021.3069, doi:10.21070/acopen.4.2021.3069.