RT Journal Article SR Electronic T1 Development of the Gastrointestinal Tract JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 456 OP 456 DO 10.1136/gut.49.3.456a VO 49 IS 3 A1 L WEAVER YR 2001 UL http://gut.bmj.com/content/49/3/456.2.abstract AB