RT Journal Article SR Electronic T1 Defensive medicine starts at the top in United States JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E335 OP E336 DO 10.1503/cmaj.109-3236 VO 182 IS 8 A1 Cal Woodward YR 2010 UL http://www.cmaj.ca/content/182/8/E335.abstract