Verma, L., P. K. Chaudhary, C. Gupta, and U. Saroj. “A Comparative Study of Tapentadol Versus Tramadol in the Treatment of Low Back Pain”. International Journal of Basic & Clinical Pharmacology, vol. 9, no. 7, June 2020, pp. 1064-8, doi:10.18203/2319-2003.ijbcp20202942.