Kappelman MD, Rifas-Shiman SL, Kleinman K, Ollendorf D, Bousvaros A, Grand RJ, Finkelstein JA
The prevalence and geographic distribution of Crohn's disease and ulcerative colitis in the United States.
Clin Gastroenterol Hepatol. 2007;5(12):1424-9. PubMed Abstract