Kharat, R. et al. 2015. Estimation of Tramadol Hydrochloride in Bulk and Formulation by Second Order Derivative Area Under Curve UV-Spectrophotometric Methods. International Journal of Advances in Scientific Research. 1, 7 (Sep. 2015), 308–312. DOI:https://doi.org/10.7439/ijasr.v1i7.1989.