Dedi Irawan, Bornok Sinaga, Elmanani Simamora. Developing a Learning Tool Based on the Problem-Based Learning Model to Improve Students’ Problem Solving and Collaboration Skills. j. perspektif [Internet]. 2026 May 11 [cited 2026 May 14];10(1):237-4. Available from: http://perspektif.uinsgd.ac.id/index.php/JP/article/view/458