1. Controlled trial of azathioprine in Crohn's disease;Willoughby, J.M.T.; Kumar, P.J.; Beckett, J.; Dawson, A.M.;Lancet,1971
2. A controlled trial of azathioprine in Crohn's disease;Rosenberg, J.L.; Levin, B.; Wall, A.J.; Kirsner, J.B.;Dig Dis,1975
3. Double-blind withdrawal trial of azathioprine as maintenance treatment for Crohn's disease;O'Donoghue, D.P.; Dawson, A.M.; Powell-Tuck, J.; Bown, R.L.; Lennard-Jones, J.E.;Lancet,1978
4. Treatment of Crohn's disease with 6-mercaptopurine, a long-term, randomized, double-blind study;Present, D.H.; Korelitz, B.I.; Wisch, N.; Glass, J.L.; Sachar, D.B.; Pasternack, B.S.;NEnglJMed,1980
5. Azathioprine combined with prednisolone or monotherapy with prednisone in active Crohn's disease;Ewe, K.; Press, A.F.; Singe, C.C.; Stufler, M.; Ueberschaer, B.; Hommel, G.;Gastroenterology,1993