1. Undertreatment of medical inpatients with narcotic analgesics;Marks;Ann Intern Med,1973
2. Management of pain in elderly patients with cancer;Bernabei;JAMA,1998
3. Effective pain management for cancer patients;Bonica,1994
4. Institute of Medicine. Approaching death: improving care at the end of life,1997
5. Analysis of narcotic usage in the treatment of postoperative pain;Sriwatanakul;JAMA,1983