title: First endoscopic appearance of ulcerative colitis.
authors.affiliation: Department of Gastroenterology and Hepatology, Leiden University Medical Centre, Albinusdreef 2, 2333 AZ Leiden, The Netherlands.
authors.forename: W H
authors.initials: WH
authors.lastname: De Vos Tot Nederveen Cappel
authors.forename: A M J
authors.initials: AM
authors.lastname: Langers
authors.forename: D W
authors.initials: DW
authors.lastname: Hommes