“Analytical Methods Validation of Retinoic Acid and Hydroquinone Using Ultra High Performance Liquid Chromatography in Medicinal Cream”. Pharmaceutical and Biomedical Sciences Journal (PBSJ) 1, no. 1 (December 13, 2019): 7–12. Accessed March 2, 2026. https://journal.uinjkt.ac.id/pbsj/article/view/12689.