The internet is full of information. Some of it is very good, some of it is not. Anybody can publish information to the web, which means you should use caution when citing any source you find online. Wikipedia is a good example of this -- there might be very good information there, and generally is a fine place to just gather background information about a topic, but you probably don't want to use it as a resource in your final paper. However, if the links at the bottom of the article are valid sources, you may be able to use those.