Gao, Hong-Wen. “Improvement of Primary- Secondary Wavelengths Spectrophotometric Determination of Trace Amounts of Sulfide in Water”. Asian Journal of Chemistry 11, no. 3 (March 30, 2010): 867–872. Accessed July 23, 2024. https://asianpubs.org/index.php/ajchem/article/view/23391.