J. LIANG†, J. ZHAO, Y. YE, Q. HU*†, and G. YANG†, “Study on Solid Phase Extraction and Spectrophotometric Determination of Gold with 5-(2-Hydroxy-4-sulfo-5- chlorophenolazo)thiorhodmine as Chromogenic Reagent”, ajc, vol. 22, no. 1, pp. 45–50, Dec. 2009.