As part of the publication process, articles in scholarly journals are reviewed by committees of other notable scholars. Such reviewers are considered to be the writer's peers.
Finding peer-reviewed articles:
When searching for articles in a general database limit your search to peer-reviewd journals.
Journal directories will help you identify peer-reviewed journals.
See Tutorial Scholarly vs Popular Periodicals. You Tube Vanderbilt University Peabody Library. August 24, 2007. [3:11 minutes]