1. Opioids used in primary care for the management of pain: A pharmacologic, pharmacotherapeutic, and pharmacodynamics overview;Barkin,2006
2. Opioids and the immune system;Sacerdote;Palliat Med.,2006
3. Opioids: A practical guide and new developments;Epstein,2012
4. Antinociceptive effects of oxymorphone-butorphanol-acepromazine combination in cats;Briggs;Vet Surg.,1998
5. Preventive therapy for nausea and vomiting in patients on opioid therapy for non-malignant pain in rheumatology;Scotto di Fazano;Therapie,2002