Purba, Nildahayani, and Suheri Lubis. “Efforts to Improve Students’ Learning Outcomes Using the Problem Based Learning Method in Islamic Education at SD Negeri 081228 Sibolga”. KOPELMA: Scientific Journal of Education and Teaching, vol. 1, no. 1, June 2024, pp. 165-71, https://journal.mgedukasia.or.id/index.php/kopelma/article/view/339.