RT Journal Article SR Electronic T1 Peptic ulcer and its drug causations. The role of non-steroidal anti-inflammatory drugs JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 231 OP 231 DO 10.1136/gut.28.2.231 VO 28 IS 2 A1 M J S Langman YR 1987 UL http://gut.bmj.com/content/28/2/231.abstract AB