RT Journal Article SR Electronic T1 On socioeconomic gradients in cancer registry data quality JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 551 OP 551 VO 60 IS 6 A1 Francis P Boscoe A1 Colleen Sherman YR 2006 UL http://jech.bmj.com/content/60/6/551.abstract AB