The Learning Page-Getting Started: Cite Sources
http://rs6.loc.gov/learn/start/cite/index.html

This guide is intended to help users prepare citations for electronic resources from the Library of Congress Web site. The purpose of a works cited document is to acknowledge the source of information and give as much detail as possible to find the source of that information at a later date. Consistency and the intended audience are the guiding principles to the following suggestions.