Shah, S.S., and R.G. Parmar. “Spectrophotometric Determination of Cu(II) Using 2-Hydroxy-4N-Butoxy-5-Bromo Acetophenone Oxime”. Asian Journal of Chemistry, vol. 22, no. 3, Mar. 2010, pp. 1717-22, https://asianpubs.org/index.php/ajchem/article/view/11327.