1. Pain in general practice. Pain as a cause of patient-doctor contact;Frolund;Scand J Prim Health Care,1986
2. Defeating pain. The war against a silent epidemic;Wall,1991
3. The prevalence of pain complaints in a general population;Crook;Pain,1984
4. Taylor H, Morency N. The Nuprin pain report. Report No.851017, New York, Louis Harris and Associates, 1985.
5. The prevalence of pain in a general population;Andersen;Pain,1987