Yuliyana, Yuliyana, Hesti Marliza, Mawardi Badar, and Yunisa Friscia Yusri. “Analysis of Caffeine Levels in Imported Coffee Drinks Circulating in Batam City by Using the UV Spectrophotometric Method: Analisis Kadar Kafein Pada Minuman Kopi Import Yang Beredar Dikota Batam Dengan Menggunakan Metode Spektrofotometri UV”. Ahmar Metastasis Health Journal 1, no. 3 (December 31, 2021): 106–111. Accessed October 29, 2025. http://journal.ahmareduc.or.id/index.php/AMHJ/article/view/62.