Desai, J.J., et al. “2’-Hydroxy-4’-Ethoxy-4-Methoxychalcone Oxime As an Analytical Reagent for Copper”. Asian Journal of Chemistry, vol. 11, no. 2, Mar. 2010, pp. 519-22, https://asianpubs.org/index.php/ajchem/article/view/23315.