Dykstra LA, Granger AL, Allen RM, Zhang X, Rice KC. Antinociceptive effects of the selective delta opioid agonist SNC80 alone and in combination with mu opioids in the squirrel monkey titration procedure. Psychopharmacology (Berl). 2002 Oct 1;163(3-4):420-9.
Allen RM, Granger AL, Dykstra LA. Dextromethorphan potentiates the antinociceptive effects of morphine and the delta-opioid agonist SNC80 in squirrel monkeys. J Pharmacol Exp Ther. 2002 Feb 1;300(2):435-41.
Lehmann K, Radbruch L, Gockel HH, Neighbors D, Nuyts G. Costs of opioid therapy for chronic nonmalignant pain in Germany: an economic model comparing transdermal fentanyl (Duragesic) with controlled release morphine. Eur J Health Econ. 2002;3:111-9. doi: 10.1007/s10198-002-0097-6.
Rothman KJ, Wepsic JG. Side of facial pain in trigeminal neuralgia. J Neurosurg. 1974 Jan 1;40(4):514-6.