PT - JOURNAL ARTICLE ED - , TI - Correction AID - 10.1503/cmaj.091106 DP - 2009 Jul 07 TA - Canadian Medical Association Journal PG - 61--61-c VI - 181 IP - 1-2 4099 - http://www.cmaj.ca/content/181/1-2/61.4.short 4100 - http://www.cmaj.ca/content/181/1-2/61.4.full SO - CMAJ2009 Jul 07; 181