Remember: you can search the PubMed database and look for these journals (aka: source) in your results, or you can go to Journals & eBooks on the library homepage and click on Find Journals. Once the journal is displayed, you can "search within" it.
American Journal of Public Health
JAMA (Journal of the American Medical Association)
Journal of Health & Social Behavior
Medical Care Research and Review
NEJM (New England Journal of Medicine)
Preventing Chronic Disease (open access)
The Public Health guide linked below has the link to PubMed (in the Databases - Core tab) as well as information from Purdue OWL on APA citation.
Part 1: Comparing types of information sources
Part 2: Searching for academic journal articles