PARHAM, H., et al. “Sequential-Constant Current Coulometric Determination of Sulfite-Thiosulfate and Or Sulfite-Ascorbic Acid in a Solution”. Asian Journal of Chemistry, vol. 19, no. 7, Mar. 2010, pp. 5123-8, https://asianpubs.org/index.php/ajchem/article/view/13113.