RT Journal Article SR Electronic T1 Hygieia JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 544 OP 544 DO 10.1136/jech.57.7.544 VO 57 IS 7 A1 Muir, M YR 2003 UL http://jech.bmj.com/content/57/7/544.abstract AB