Information sources are considered scholarly or academic if they are written by experts (also known as scholars). The experts may be an individual author, a group of authors, or a group which is considered an authority (like the Centers for Disease Control and Prevention, a department of the US Government.)
Not sure? If you are unsure whether your source is scholarly, ask a librarian or your instructor. We'll help you decide, and teach you about how we make those complex decisions too.
The most common types of scholarly sources are: