It is an extremely lengthy and comprehensive process. The studies I have referred to were all published in such journals as the Canadian Journal of Psychiatry and the Journal of Traumatic Stress. Others will be published in these journals and others as well. The material is usually reviewed by two or three peers, in addition to the editor of the journal. As a general rule, when you submit an article or a study, you receive comments from the reviewers and are asked to clarify or change certain things. It is a very lengthy process, but an extremely reliable one as well.
On March 22nd, 2007. See this statement in context.