Tawfic, Qutaiba Amir, Ali S. Faris, and Rohit R. Date. 2013. “The Dilemma of Opioid-Induced Hyperalgesia and Tolerance in Chronic Opioid Therapy”. Sultan Qaboos University Medical Journal 13 (1):185-87. https://journals.squ.edu.om/index.php/squmj/article/view/1777.