Set the article name in quotes, with a period at the end of the article name inside of the quotes. This is unlike APA format, which leaves off the quotations in order to conserve space.
State that Wikipedia is your source, in italics, with a period after the website name. Do not use ".com" as part of the site name, since the actual name of the site is Wikipedia.
Follow this with the date that you initially accessed the site during your research. If the article was updated between your viewings, if the content changed significantly and if you used the new content, you may have to cite multiple access dates as separate pages.
End your citation with the URL. This doesn't involve a simple "www.wikipedia.com." You should start with the almost ubiquitous http:// and make sure to note whether it is an English site or not. Don't fail to put the URL for the article as it appears in your location bar in your browser.