Rahmayani S, Yogica R. LITERATURE STUDY THE EFFECT OF VARIATIONS OF THE APPLICATION OF THE PROBLEM BASED LEARNING (PBL) MODEL ON STUDENTS ’LEARNING INTEREST IN MIDDLE SCHOOLS. universe [Internet]. 2021 Dec. 30 [cited 2026 Jun. 9];2(2):185-91. Available from: http://universe.ppj.unp.ac.id/index.php/universe/article/view/86