Patel, Vanadana, et al. “Simultaneous Determination of Atorvastatin Calcium and Ezetimib by Ratio Spectra Derivative Spectrophotometry and Reverse Phase-High Performance Liquid Chromatography”. Asian Journal of Chemistry, vol. 22, no. 4, Mar. 2010, pp. 2511-7, https://asianpubs.org/index.php/ajchem/article/view/11437.