RT Journal Article SR Electronic T1 An introduction to quality assurance in health care JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP 627 OP 627 VO 58 IS 7 A1 Øvretveit, John YR 2004 UL http://jech.bmj.com/content/58/7/627.1.abstract AB