RT Journal Article SR Electronic T1 Author response: oral contraceptives and Crohn’s disease JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 854 OP 854 DO 10.1136/gutjnl-2014-308509 VO 64 IS 5 A1 Khalili, Hamed A1 Chan, Andrew T YR 2015 UL http://gut.bmj.com/content/64/5/854.2.abstract AB