RT Journal Article SR Electronic T1 Physicians and climate change policy: We are powerful agents of change JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 307 OP 307 DO 10.1503/cmaj.150139 VO 187 IS 5 A1 Kirsten Patrick YR 2015 UL http://www.cmaj.ca/content/187/5/307.abstract