Baines MJ: Symptom control in advanced gastrointestinal cancer. Eur J Gastroenterol Hepatol 12: 375-379, 2000
Goldstein FJ: Adjuncts to opioid therapy. J Am Osteopath Assoc 102: S15-S21, 2002
Ready LB: Acute perioperative pain. In Anesthesia, edu 5. Edited by Miller RD. Philadelphia: Churchill Livingstone Inc, 2323-2350, 2000
Inturrisi CE: Clinical pharmacology of opioids for pain. Clin J Pain 18: S3-S13, 2002
Sora I, Elmer G, Funada M, et al: Mu opiate receptor gene dose effects on different morphine actions: evidence for differential in vivo mu receptor reserve. Neuropsychopharmacology 25: 41-54, 2001