KANNAPPAN, N., et al. “Simultaneous Spectrophotometric Estimation of Ciprofloxacin and Tinidazole in Tablets Using Orthogonal Polynomial Function Method”. Asian Journal of Chemistry, vol. 19, no. 4, Mar. 2010, pp. 2637-41, https://asianpubs.org/index.php/ajchem/article/view/13356.