What type of article do you want? What kind of article have you found?
Popular articles are usually written by a journalist for a general audience. The sources of the information presented are not usually cited.
Scholarly articles are written by scholars and experts in a particular field. Before an article is published it will be reviewed and evaluated by a panel of other academics or experts in that field. This is called peer-review. A peer-reviewed or scholarly article usually follows a particular format including:
An annotated bibliography is NOT the same as compiling a Reference List or Works Cited page at the end of a research paper. The links below include the "basics" to help you create an annotated bibliography.