Pravita Saktiyani, and Hari Sutrisno. “IMPLEMENTATION OF LEARNING MODELS PBL- REDIPPER FOR INCREASE ABILITY THINK CRITICAL AND COLLABORATION STUDENTS ON ATOMIC STRUCTURE MATERIAL”. International Journal of Social Science, Educational, Economics, Agriculture Research and Technology (IJSET), vol. 5, no. 7, May 2026, pp. 3442-7, https://ijset.org/index.php/ijset/article/view/1952.