Wulanndari, Indah. “Validity of Problem Based Learning (PBL) Worksheets to Improve Learners’ Creative Thinking Skills on Renewable Energy Study Materials”. IPF: Inovasi Pendidikan Fisika 12, no. 3 (October 1, 2023): 57–67. Accessed July 6, 2025. https://ejournal.unesa.ac.id/index.php/inovasi-pendidikan-fisika/article/view/57136.