ELP

The purpose of a citation is to provide the reader with information to find the source of the author's facts or ideas. A citation includes, at the very least, the title, author, source of publication, and date of publication. 

Citation styles, such as MLA, APA, and Chicago/Turabian, are sets of rules that determine how citations are formatted. Different disciplines favor certain styles, so check with your professor if you are unsure which format to use for your coursework. 

A DOI is a unique code assigned to a digital object (such as an article from a database) used for location and identification. You'll often see the DOI for an article listed on its first page. DOIs allow you to connect directly to a specific article, avoiding potential problems like broken links or missing URLs. To find the DOI for an article you're citing, use the Lookup link. To find an article from a DOI, use the DOI resolver.