Leswana, N., and C. Sinaga. “Identification Retinoic Acid Content in Online Whitening Cream Sold in Samarinda City Using Thin Layer Chromatography (TLC) and Spectrophotometry UV-Visible Methods”. Journal of Pharmaceutical And Sciences, Vol. 5, no. 2, July 2022, pp. 174-80, doi:10.36490/journal-jps.com.v5i2.112.