Muralikrishna, U., and Akella Sivaramakrishna. “Simultaneous Spectrophotometric Determination of Copper(II) and Nickel(II) Using Dimethylglyoxime As a Reagent”. Asian Journal of Chemistry, vol. 13, no. 1, Mar. 2010, pp. 289-93, https://asianpubs.org/index.php/ajchem/article/view/22566.