1. Hospital caseloads in Liverpool, New England and Uppsala;Pearson, R.J.C.; Smedby, B.; Berfensam, R.;Lancet,1968
2. Regional variations in the use of common surgical procedures: within and between England and Wales, Canada and the United States of America;McPherson, K.; Strong, P.M.; Epstein, A.; Jones, L.;Soc Sci Med,1981
3. Small area variations in the use of common surgical procedures: and international comparison of New England, England and Norway;McPherson, K.; Wennberg, J.E.; Hovind, O.B.; Clifford, P.;N EnglJ7 Med,1982
4. Gallbladder disease and cholecystectomy are independently variable;Bateson, M.C.;Lancet,1984
5. Do cholecystectomy rates vary with geographical variations in the prevalence of gallstones?]7 Epidemiol;McPherson, K.; Strong, P.M.; Jones, L.; Britton, B.J.;Community Health,1985