RT Journal Article SR Electronic T1 Barriers to physical activity and socioeconomic position: implications for health promotion. JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 191 OP 192 DO 10.1136/jech.53.3.191 VO 53 IS 3 A1 D J Chinn A1 M White A1 J Harland A1 C Drinkwater A1 S Raybould YR 1999 UL http://jech.bmj.com/content/53/3/191.abstract AB