1. Newberger PE, Sallan SE. Chronic pain: principles of management. J Pediatr 1981;98:180–9.
2. Diamond AW, Coniam SW. The management of chronic pain. New York: Oxford University Press, 1991.
3. Hendler N. Diagnosis and nonsurgical management of chronic pain. New York: Raven Press, 1981.
4. Loeser JD, Egan KJ, editors. Managing the chronic pain patient. New York: Raven Press, 1989.
5. Portenoy RK. Chronic opioid therapy in nonmalignant pain. J Pain Symptom Manag 1990;5(1) Suppl.:46–62.