RT Journal Article SR Electronic T1 Is proficiency testing in cervical cytology proficient? JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 536 OP 537 DO 10.1136/jcp.50.7.536 VO 50 IS 7 A1 A Herbert YR 1997 UL http://jcp.bmj.com/content/50/7/536.abstract AB