J. Reed, J. Thistlethwaite, and J. Huppert. The Journal of Adolescent Health: Official Publication of the Society for Adolescent Medicine, 41 (1):
14--18(July 2007)PMID: 17577529.
P. Veugelers, and A. Fitzgerald. CMAJ: Canadian Medical Association Journal = Journal De l'Association Medicale Canadienne, 173 (6):
607--613(September 2005)PMID: 16157724.