A review article is a secondary source...it is written about other articles, and does not report original research of its own. Review articles are very important, as they draw upon the articles that they review to suggest new research directions, to strengthen support for existing theories and/or identify patterns among exising research studies. For student researchers, review articles provide a great overview of the exisiting literature on a topic. If you find a literature review that fits your topic, take a look at its references/works cited list for leads on other relevant articles and books!