A. M. A. Nasution, Ngatirah, H. Oktavianty, and N. E. A. Nasution, “The Effect of Variations in the Water-to-Coffee-Powder Ratio on the Water Content and Caffeine Content of Sigarar Utang Instant Arabica Coffee”, J. Sci. Technol. Educ., vol. 2, no. 2, pp. 75–80, Dec. 2023.