Saluat Siahaan. “IMPROVE COLLIGATIVE PROPERTIES SKILLS AND PROBLEM SOLVING ABILITY OF SMA NEGERI 1 BABALAN CLASS XII STUDENTS USING MODEL PROBLEM BASED LEARNING (PBL)”. International Journal of Education and Literature 2, no. 2 (August 30, 2023): 21–38. Accessed April 17, 2025. https://ijel.asia/index.php/ijel/article/view/70.