RT Journal Article SR Electronic T1 Towards a new era with safer ยต-opiate receptor analgesia JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP gutjnl-2021-324618 DO 10.1136/gutjnl-2021-324618 A1 Michael Camilleri YR 2021 UL http://gut.bmj.com/content/early/2021/04/18/gutjnl-2021-324618.abstract AB