RT Journal Article SR Electronic T1 Estimates of familial risks from family data are biased when ascertainment of families is not independent of family history JF Gut JO Gut FD BMJ Publishing Group Ltd and British Society of Gastroenterology SP 1162 OP 1163 DO 10.1136/gut.2010.223826 VO 60 IS 8 A1 Win, Aung Ko A1 Hopper, John L A1 Jenkins, Mark A YR 2011 UL http://gut.bmj.com/content/60/8/1162.abstract AB