Issa, Y. M., H. M. Abddel-Fattah, and M. A. S. Allahgi,
"Spectrophotometric Determination of Benzethonium Chloride using some Chromotropic Acid Azo Dyes",
Egypt. J. Chem., vol. 62, issue Special issue part 1, innovation in chemistry. December 2019, pp. 267-279 , 2019.