1. Calkins, B. & Mendeloff, A. The epidemiology of idiopathic inflammatory bowel disease, in Inflammatory Bowel Disease (eds Kirsner, J.B. & Shorter, R.G.) 31–68 (Williams and Wilkins, Baltimore, 1995).
2. Satsangi, J., Rosenberg, W.M.C. & Jewell, D.P. The prevalence of inflammatory bowel disease in relatives of patients with Crohn's disease. Eur. J. Gastro. Hepatol. 6, 413–416 (1994).
3. Probert, C.S.J., Jayanthi, V., Hughes, A.D., Thompson, J.R., Wicks, A.C.B. & Mayberry, J.F. Prevalence and family risk of ulcerative colitis and Crohn's disease: an epidemiological study among Europeans and South Asians in Leicestershire. Gut 34, 1547–1551 (1993).
4. Yang, H. et al. Familial empirical risks for inflammatory bowel disease: differences between Jews and non-Jews. Gut 34, 517–524 (1993).
5. Tysk, C., Lindberg, E., Järnerot, G. & Flodérus-Myrhed, B. Ulcerative colitis and Crohn's disease in an unselected population of monozygotic and dizygotic twins. A study of heritability and the influence of smoking. Guf 29, 990–996 (1988).