MLA Handbook for Writers of Research Papers, 6th Ed by 
Mla Made Easy by The citation style you use depends on a variety of factors. Many disciplines tend to use one particular style over another (Chicago for art, for example). Your instructors may require you use a certain style, so ask about which manual to use before you start your research. If you are publishing one of your works, your editor may require that you use of a certain style.
If you aren't required to use a certain style, use one that you are comfortable with and that best fits your needs. Just follow the guidelines and be consistent.