This article is related to two Cochrane Protocols or Reviews which are published in the Cochrane Database of Systematic Reviews where they will be regularly updated. Cochrane Reviews are of a high standard and are not evaluated by CRD. The links are:
http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD003008/frame.html
http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000210/frame.html