RT Journal Article SR Electronic T1 Physical punishment of children: lessons from 20 years of research JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP cmaj.101314 DO 10.1503/cmaj.101314 A1 Joan Durrant A1 Ron Ensom YR 2012 UL http://www.cmaj.ca/content/early/2012/02/06/cmaj.101314.abstract AB