AFSHAR, Z.GH., and H. PARHAM. “Determination of Trace Amounts of Cationic Surfactant Cetyl Trimethyl Ammonium Bromide by Liquid-Liquid Extraction-Spectrophotometry Method”. Asian Journal of Chemistry, vol. 22, no. 4, June 2010, pp. 3009-13, https://asianpubs.org/index.php/ajchem/article/view/11549.