Ali Taher, M. (2010). Derivative Spectrophotometric Determination of Trace Manganese after Separation and Preconcentration with the Ion Pair of 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol and Ammonium Tetraphenylborate . Asian Journal of Chemistry, 14(1), 107–116. Retrieved from https://asianpubs.org/index.php/ajchem/article/view/21959