В инете много что пишутhttp://www.google.com/search?client=opera&rls=ru&q=%D0%BF%D1%83%D1%82%D0%B8%D0%BD+%D0%B8+%D0%BA%D0%B0%D0%B1%D0%B0%D0%B5%D0%B2%D0%B0&sourceid=opera&ie=utf-8&oe=utf-8