RT Journal Article SR Electronic T1 Prevalence of ghostwriting spurs calls for transparency JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E161 OP E162 DO 10.1503/cmaj.109-3036 VO 181 IS 8 A1 Roger Collier YR 2009 UL http://www.cmaj.ca/content/181/8/E161.abstract