Effendi, Novicha, and Iryani Iryani. “Validity of Buffer Solution E-Module Based on Problem Based Learning”. Entalpi Pendidikan Kimia 4, no. 3 (August 28, 2023): 27-35. Accessed July 5, 2024. http://entalpipendidikan.ppj.unp.ac.id/index.php/epk/article/view/350.