epidemiological research studies

Search health care journals for examples of epidemiological research studies. Classify each study as descriptive, cross-sectional, retrospective, prospective, or experimental and explain why you have classified it as such. Find examples for eachCite all sources. Minimum of at least five (5)please a Minimum of at least five (5) . thank you.and please use Library(at least 2 sources) :http://infotrac.galegroup.com/default/tam53788?db=PPNU