RT Journal Article SR Electronic T1 Social Dilemmas in Cancer Prevention JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 174 OP 174 DO 10.1136/jech.44.2.174-b VO 44 IS 2 A1 Alwyn Smith YR 1990 UL http://jech.bmj.com/content/44/2/174.3.abstract AB