TY - JOUR AU - Engel, C TI - Efficacy of annual colonoscopic surveillance in individuals with hereditary nonpolyposis colorectal cancer JO - Clin Gastroenterol Hepatol IS - 02 VL - 8 PY - 2010 DO - 10.1016/j.cgh.2009.10.003 SP - 174 EP - 182 N1 - et al. ER -