A. P. Anggraini, M. Fildzah Arifah, F. U. Sayyidah Yahya, and D. Nurhasanah, “The Effect of Extraction Time Variation on Caffeine Content in Robusta Coffee Extract using Ultrasound-Assisted Extraction Method”, J. Food Pharm. Sci, vol. 13, no. 1, pp. 76-86, Mar. 2025.