TY - JOUR AN - 568 AU - Kaltz,B. AU - Bokemeyer,B. AU - Hoffmann,J. TI - Surveillance colonoscopy in ulcerative colitis patients in Germany. JO - Z Gastroenterol PY - 2007 VL - 45 SP - 325-331 M2 - 325 DO - 10.1055/s-2007-962987 ER -