Reference only for this article. Year: 2014 Bibliography: Barlow J, Smailagic N, Huband N, Roloff V, Bennett, C. 2014. Cochrane Database of Systematic Reviews 2014, Issue 5. Art. No.: CD002020. DOI: 10.1002/14651858.CD002020.pub4. REVIEW. Authors: Barlow, Smailagic, Huband, Roloff, Bennett