RT Journal Article SR Electronic T1 Comparative physiology of the vertebrate digestive system JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 1029 OP 1029 DO 10.1136/gut.30.7.1029-a VO 30 IS 7 A1 David Wingate YR 1989 UL http://gut.bmj.com/content/30/7/1029.2.abstract AB