Nasution IYL, Mulyono M, Surya E. Development of Mathematics Learning Tools Using Problem Based Learning Model to Improve Problem Solving Skills and Learning Motivation. j. perspekt. [Internet]. 2024 Oct. 30 [cited 2025 Jun. 20];8(2):250-62. Available from: http://perspektif.uinsgd.ac.id/index.php/JP/article/view/306