RT Journal Article SR Electronic T1 Acute upper gastrointestinal bleeding: identifying low risk patients JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 1641 OP 1641 DO 10.1136/gutjnl-2012-302162 VO 61 IS 11 A1 Richard F A Logan A1 Sarah Hearnshaw A1 Derek Lowe A1 Simon P L Travis A1 M Stephen Murphy A1 Kel R Palmer YR 2012 UL http://gut.bmj.com/content/61/11/1641.1.abstract AB