KARIM-NEZHAD, GHASEM, et al. “Simultaneous Determination of Copper and Iron in Biological Samples With 1-(2-Pyridylazo)-2-Naphthol in Anionic AOT Micellar Solution Using Derivative Spectrophotometry”. Asian Journal of Chemistry, vol. 21, no. 4, Mar. 2010, pp. 2565-72, https://asianpubs.org/index.php/ajchem/article/view/12474.