Comparative Trial of Remission Prophylaxis in Quiescent Crohn’s Disease with Oral 4-Aminosalicyclic Acid Versus 5-Aminosalicylic Acid Slow Release Tablets - Stefanie Howaldt; Andreas Raedler; H-Christian Reinecker; Daniela Berghaus; Susanne Hoyer; Barbara Kaiser; Stefan Schreiber (Canadian Journal of Gastroenterology)