Sihombing, Robinson. “APPLICATION OF THE PROBLEM BASED INSTRUCTION (PBI) LEARNING MODEL ON TUBE MATERIALS TO IMPROVE STUDENT LEARNING OUTCOMES”. Afore : Jurnal Pendidikan Matematika 2, no. 2 (October 20, 2023): 115-127. Accessed July 27, 2025. https://jurnal.uniraya.ac.id/index.php/Afore/article/view/1135.