Rai, H.C., Patanjali Kashyap, Shiv Ranjan Kumar, and Shalamuddin. 2010. “Spectrophotometric Determination of Copper(II)with Phenanthrenequinone Monosemicarbazone”. Asian Journal of Chemistry 16 (1):304-8. https://asianpubs.org/index.php/ajchem/article/view/19602.