RT Journal Article SR Electronic T1 Value and usability of unpublished data sources for systematic reviews and network meta-analyses JF Evidence Based Medicine JO Evid Based Med FD BMJ Publishing Group Ltd SP 208 OP 213 DO 10.1136/ebmed-2016-110494 VO 21 IS 6 A1 Nicholas James Anthony Halfpenny A1 Joan Mary Quigley A1 Juliette Catherine Thompson A1 David Alexander Scott YR 2016 UL http://ebm.bmj.com/content/21/6/208.abstract AB