Canadian Medical Association Journal • November 21, 2006; 175 (11). doi:10.1503/cmaj.060863.
http://www.cmaj.ca/cgi/content/full/175/11/1399
Evan Wood, Mark W. Tyndall, Julio S. Montaner and Thomas Kerr
Full Text PDF - http://www.cmaj.ca/cgi/reprint/175/11/1399