Once you are "inside" an article, most library databases (Ebsco, Proquest, etc) now offer the ability to format citations. You can usually find this option as part of the print/save/email function, or in a "cite this article" link.
Make sure and check these before listing them in your References/Works Cited page, as some may not be 100% accurate.
Citation generators can help you to create citations and bibliographies. If you use one of the citation generators, be sure to review your results carefully. If in doubt, refer to the appropriate style manual for definitive information.