CHATTI I, WOILLARD J-B, MILI A, CREVEAUX I, CHARFEDDINE IB, FEKI J, LANGLAIS S, BEN FATMA L, SAAD A, GRIBAA M, LIBERT F. Genetic Analysis of Mu and Kappa Opioid Receptor and COMT Enzyme in Cancer Pain Tunisian Patients Under Opioid Treatment. Iran J Public Health. 2017;46(12):1704-1711.