RT Journal Article SR Electronic T1 Constipation JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 476 OP 476 DO 10.1136/gut.36.3.476-a VO 36 IS 3 A1 K W Heaton YR 1995 UL http://gut.bmj.com/content/36/3/476.2.abstract AB