Quyền, Phạm, Đỗ Hân, Nguyễn Hậu, and Lê Trí. “Preparation of Cough Syrup Containing Dextromethorphan HBr, Promethazine HCl and Preliminary Assessment of Formulation Stability”. VNUHCM Journal of Health Sciences 2, no. 2 (August 25, 2021): 214-221. Accessed January 28, 2023. http://stdjhs.scienceandtechnology.com.vn/index.php/stdjhs/article/view/474.