Wongsuwan, Peangjai. “Simultaneous Analysis of Hydroquinone and Retinoic Acid in Cosmetics by High Performance Liquid Chromatography”. Journal of Health Science of Thailand 23, no. 2 (November 28, 2017): 362–368. Accessed December 8, 2025. https://www.thaidj.org/index.php/JHS/article/view/688.