Peer Review is the process that allows readers and other researchers (like yourself) to judge whether a journal article has been deemed credible by the academic community. Before an article is published in a journal it goes through a series of edits by anonymous scholars who study the same topics to ensure the information is correct, the author(s) have done proper research, and the information is free from bias. While this does not mean that every peer-reviewed article is "True," you can rest easy that others have read it and are willing to stand behind its credibility.
In short, when you find an article that is peer-reviewed, you can feel confident using it for your assignments. Check out these peer-reviewed journals available through the Library: