The Cochrane Library will usually provide a ready-made citation at the top of each document. Click on "View/save citation" to the right of the DOI.
Author(s). Review title. Cochrane Database of Systematic Reviews publication year, Issue number, Art. No:. DOI.
Hemila H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.:CD000980. DOI:10.1002/14651858. CD000980.pub4.