I. Dewan, A. Saha, S. A. Islam, M. Gazi, T. Amin, and S. F. Chowdhury, “Study and Evaluation of Release Kinetics of Tramadol HCl from Lipid Based Sustained Release Capsules by Melt Matrix”, Dhaka Univ. J. Pharm. Sci, vol. 11, no. 2, pp. 137–145, Apr. 2013.