1. Cohen FL (1980) Postsurgical pain relief: patients’ status and nurses’ medication choices. Pain 9: 265–74
2. Maier C, Raetzel M, Wulf H (1994) Audit in 1989 and 1994 of the Department of anesthesiology and Intensive Care, Hospital of Christian-Albrechts-University, Schwanen weg 21, D 24105, Kiel, Germany
3. Neugebauer E, Hempel K, Sauerland S et al (1998) The status of perioperative pain therapy in Germany. Results of a representative, anonymous survey of 1000 surgical clinics. Chirurg 69: 461–466
4. Donovan M, Dillon P, McGuire L (1983) Incidence and characteristics of pain in a sample of medical-surgical inpatients. Pain 30: 69–78
5. Kuhn S, Cooke K, Collins M, et al (1990) Perceptions of pain relief after surgery. BMJ 300: 1687–1690