This video describes the differences between popular and scholarly sources. It was created by Carnegie Vincent Library at Lincoln Memorial University.
Ulrich's International Periodicals Directory provides infromation on over 210,000 regularly and irregularly published journals. If you aren't sure if an article you found is scholarly, Ulrich's is a great place to look for more information.
If you want to be absolutely sure a journal is peer-reviewed, use the database Ulrich's International Periodicals Directory. Look up the journal by title. Titles that are peer-reviewed are indicated by the black and white referee's jersey ("refereed" is another term for peer-reviewed). Note that there may be some parts of the journal (e.g. letters to the editor, book reviews, etc.) that are not peer- reviewed.
What are scholarly sources?
Scholarly sources are:
written by and for researchers and scholars.
explorations of research and ideas to increase knowledge and understanding.
conversations between scholars on research, methods, and theories.