The two most common guides for citing sources are MLA (Modern Language Association, commonly used in the humanities) and APA (American Psychological Association, commonly used in the social sciences and sciences). Ask your professor which style he or she prefers.
Note that most articles in CSM library database have the citations included - in the text of the article, or in one of the features available, e.g. "cite" or "email". This is very convenient but it is important to check whether these available citations are correct.