RT Journal Article SR Electronic T1 The need for evidence-based obstetrics JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 132 OP 133 DO 10.1136/ebm.1996.1.132 VO 1 IS 5 A1 Enkin, Murray W. YR 1996 UL http://ebm.bmj.com/content/1/5/132.abstract AB