PT - JOURNAL ARTICLE ED - , TI - The British Society of Gastroenterology AID - 10.1136/gut.15.4.335 DP - 1974 Apr 01 TA - Gut PG - 335--348 VI - 15 IP - 4 4099 - http://gut.bmj.com/content/15/4/335.short 4100 - http://gut.bmj.com/content/15/4/335.full SO - Gut1974 Apr 01; 15