Dharmasetiawani, Nani, Herman Suryadi, and Agus Firmansyah. “Quantitative Analysis of Lactose and Lactulose in Urine by High Performance Liquid Chromatography for Determination of Intestinal Lactase Activity”. Medical Journal of Indonesia 12, no. 1 (February 1, 2003): 8–12. Accessed January 21, 2025. https://mji.ui.ac.id/journal/index.php/mji/article/view/84.