Islamiati, Fitri Nur. “Project-Based Learning (PjBL) Worksheet on the Production of Whey Kefir Paper Soap”. JTK (Jurnal Tadris Kimiya) 8, no. 1 (June 29, 2023): 21–29. Accessed December 18, 2025. http://103.55.33.27/index.php/tadris-kimiya/article/view/25219.