Lestari, A. and Atun, S. 2021. The Effectiveness of E-Module on Buffer Solutions to Improve Students’ Higher-Order Thinking Skills and Self-Regulated Learning. JTK (Jurnal Tadris Kimiya). 6, 2 (Dec. 2021), 254–266. DOI:https://doi.org/10.15575/jtk.v6i2.13772.