RT Journal Article SR Electronic T1 Concussion JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 981 OP 981 DO 10.1503/cmaj.120511 VO 185 IS 11 A1 Laura Purcell A1 Jamie Kissick A1 John Rizos YR 2013 UL http://www.cmaj.ca/content/185/11/981.abstract AB