It may not be forbidden, but Wikipedia is considered to be a poor source. Reviewers for leading journals would probably not be favorable to an author using Wikipedia as a source.
Better to find a peer reviewed academic journal article for your citation.
It depends on the kind of information we are looking for. Wikipedia, in some cases, uses reliable references or sources, which are very useful. The process of verification always should be done.
Wikipedia is run by a small group of people who are quite enamored with themselves but have really very little knowledge of the material posted on their site. In fact, they are actually hostile to entries by anyone who has an actual expertise on the subject matter of an entry as they want the site to be populist. As a result, many entries have mistakes or inconsistencies that when they are corrected by a noted expert they will immediately remove. They are particularly hostile to findings from published university theses no matter how good they are. This is an important shortcoming. It is fine to use it as a point of departure but all information given needs to be verified and assumed to be incomplete or contain populist distortions. I would never cite it although I am cited on it - citations I do not trust - and if I were to make corretions to where I am cited I would expect them to angrily remove my changes. That said, as there is much useful important unpublished material that is uploaded to websites, including this one, one can cite the source if it is not otherwise available using the web address and the date recovered from the web.
Thank you All, I appreciate the responses. What I have done is that instead of directly citing from WIKIPEDIA what I did is go to the footnotes and search the original article.