Information resources reflect their creators’ expertise and credibility, and are evaluated based on the information need and the context in which the information will be used. Authority is constructed in that various communities may recognize different types of authority. It is contextual in that the information need may help to determine the level of authority required.
In your research and reading, asking yourself who created the information that you are using and what gives them their authority (or expertise) can be very helpful in deciding whether or not to cite the information.
Check out this short video from Western University on how to read a scholarly article.