Maintenance treatment with azathioprine in ulcerative colitis: outcome and predictive factors after drug withdrawal.
Cassinotti A, Actis GC, Duca P, Massari A, Colombo E, Gai E, Annese V, D'Albasio G, Manes G, Travis S, et al. Am J Gastroenterol. 2009 Nov; 104(11):2760-7. Epub 2009 Jul 21.