Damaiyanti, T., M. A. . Nasution, H. M. Nasution, and R. Yuniarti. “Determination of Caffeine Levels from Robusta Coffee Leaf Extract (Coffea Canephora Pierre Ex A. Froehner) and Arabica Coffee Leave (Coffea Arabica L.) With High-Performance Liquid Chromatography Method”. Journal of Pharmaceutical and Sciences, vol. 6, no. 4, Sept. 2023, pp. 1544-52, doi:10.36490/journal-jps.com.v6i4.257.