Karmila, A. et al. 2022. A Development of E-Learning Chemistry Based on Project Based Learning on Buffer Solution Using Then Flipped Classroom Approach in Class XI SMA/MA. INTERNATIONAL JOURNAL OF HIGH INFORMATION, COMPUTERIZATION, ENGINEERING AND APPLIED SCIENCE (JHICE). 2, 01 (Jan. 2022), 19–27. DOI:https://doi.org/10.24036/jhice/vol2-iss01/35.