Rai, H.C., and I. Chakraborti. “Spectrophotometric Determination of Rhodium(III) With Phenanthrenequinone Monosemicarbazone”. Asian Journal of Chemistry, vol. 15, no. 3, July 2012, pp. 1572-8, https://asianpubs.org/index.php/ajchem/article/view/21841.