RT Journal Article SR Electronic T1 Second-hand smoke in cars: How did the “23 times more toxic” myth turn into fact? JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 796 OP 799 DO 10.1503/cmaj.090993 VO 182 IS 8 A1 Ross MacKenzie A1 Becky Freeman YR 2010 UL http://www.cmaj.ca/content/182/8/796.abstract