Choi Bernard C K, Morrison Howard, Wong Tom, Wu Jun, Yan Yong-Ping
Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada, AL no 6701A, 120 Colonnade Road, Ottawa, Ontario, Canada.
J Epidemiol Community Health. 2007 Sep;61(9):832. doi: 10.1136/jech.2006.057752.