Yazid, E. A., Wafi, A., & Wulandari, A. E. (2021). Spectrophotometric Methods for the Determination of Caffeine in Beverages Use Solvent Extraction Techniques and Adsorption of Activated Carbon. Journal of Tropical Pharmacy and Chemistry, 5(4), 338–346. https://doi.org/10.25026/jtpc.v5i4.308