KEYVANFARD, M., & POURETEDAL, H. (2010). Catalytic Spectrophotometric Determination of Trace Amounts of Ag(I) using the Oxidation of 1,8-Dihydroxy-2-(4-sulfophenylazo)naphthalene-3,6- disulfonic Acid Trisodium Salt with Peroxodisulfate. Asian Journal of Chemistry, 19(5), 3747–3754. Retrieved from https://asianpubs.org/index.php/ajchem/article/view/13275