et.al, S. K. J. “Solvent Extraction of Copper (II) from Aqueous Solutions by New Organic Reagent 2-[(3-Hydroxy phenyl)azo]-4,5- Diphenyl Imidazole”. Al-Qadisiyah Journal of Pure Science, Vol. 18, no. 1, Aug. 2017, pp. 66-80, https://journalsc.qu.edu.iq/index.php/JOPS/article/view/382.