TY - JOUR T1 - Clinical trial participation poses ethical, practical issues JF - Canadian Medical Association Journal JO - CMAJ SP - 500 LP - 502 DO - 10.1503/cmaj.090131 VL - 180 IS - 5 AU - Ann Silversides Y1 - 2009/03/03 UR - http://www.cmaj.ca/content/180/5/500.abstract ER -