Safitri D, Napitupulu EE, Khairani N. Development of Problem-Based Learning Teaching Materials to Improve Mathematical Problem Solving Ability and Self-Efficacy Students. j. perspekt. [Internet]. 2024 Jun. 23 [cited 2025 Aug. 28];8(1):137-48. Available from: https://perspektif.uinsgd.ac.id/index.php/JP/article/view/298