RT Journal Article SR Electronic T1 Assessing allocation concealment and blinding in randomised controlled trials: why bother? JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 36 OP 38 DO 10.1136/ebm.5.2.36 VO 5 IS 2 A1 Kenneth F Schulz YR 2000 UL http://ebm.bmj.com/content/5/2/36.abstract AB