RT Journal Article SR Electronic T1 Radiographic Atlas of Colon Disease JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 339 OP 340 DO 10.1136/gut.22.4.339-a VO 22 IS 4 A1 Kelsey Fry YR 1981 UL http://gut.bmj.com/content/22/4/339.2.abstract AB