Shamsipur, M., Fakhari, A. R. (1993). 'Extraction of Traces of Copper as Tetra-Butylammonium Tetrathiocyanato Copper (II) and Its Spectrophotometric Determination Using Eriochrome Black T', Iranian Journal of Chemistry and Chemical Engineering, 12(1), pp. 39-44. doi: 10.30492/ijcce.1993.10933