Zaman, Z. A., & Kumar, D. (2017). Evaluation of analgesic effect of tapentadol, a central novel analgesic versus tramadol, a widely used opioid analgesic in treatment of low back pain: a randomized controlled trial. International Journal of Basic & Clinical Pharmacology, 2(4), 392–396. Retrieved from https://www.ijbcp.com/index.php/ijbcp/article/view/1287