HANY W.DARWISH, et al. “DEVELOPMENT AND VALIDATION OF H-POINT STANDARD ADDITION METHOD APPLIED FOR THE ANALYSIS OF BINARY MIXTURE OF AMLODIPINE AND ATORVASTATIN”. International Journal of Pharma and Bio Sciences, vol. 4, no. 2, June 2013, pp. 230-43, https://ijpbs.net/index.php/journal/article/view/2166.