Reni Tania, and Welven Aida. “PENGARUH MODEL PEMBELAJARAN PROBLEM BASED LEARNING TERHADAP KEMAMPUAN BERPIKIR KRITIS SISWA KELAS IX MATA PELAJARAN IPS DI SMP NEGERI 1 BANGUN PURBA”. Bakoba : Journal of Social Science Education 1, no. 1 (January 8, 2021): 24–33. Accessed July 6, 2022. https://journal.upp.ac.id/index.php/bakoba/article/view/587.