Referencing systematic reviews from the Cochrane Library
Author, Initials. ‘Title of review’. Cochrane Database of Systematic Reviews. Year, Issue number, Article number. DOI: number.
e.g. Loveman, E., Royle, P. and Waugh, N. ‘Specialist nurses in diabetes mellitus’. Cochrane Database of Systematic Reviews. 2003, Issue 2, Art. No. CD003286. DOI: 10.1002/14651858.
When you connect to the review on Wiley, there is a 'how to cite' feature which you can use and adapt for the Harvard style as above.
Referencing the PDFs on the Joanna Briggs Institute (JBI) database
Author (year) Evidence summary: Title. Available at: url. (Accessed: date)
e.g. Campbell, J. (2014) Evidence summary: Depression: vervain. Available at: http://ovidsp.tx.ovid.com/sp-3.14.0b/ovidweb.cgi?&S=ADGGFPGNDPDDFCCMNCLKKCIBOLFDAA00&Link+Set=S.sh.21%7c2%7csl_190 (Accessed: 10 February 2015)