Gao, Hong-Wen, Yun-Sheng Chen, and Peng-Fei Zhang. “β-Correction Spectrophotometric Investigation of Copper Chelate Solution With Acid Chrome Blue K Determination of Trace Copper ”. Asian Journal of Chemistry 11, no. 2 (March 30, 2010): 300–306. Accessed July 23, 2024. https://asianpubs.org/index.php/ajchem/article/view/23280.