Fair use refers to the limited use of copyrighted material for purposes such as criticism, comment, news reporting, teaching, or scholarship. This provision is what allows textbook authors to repeat quotes from magazine articles (as long as the original source is citied); movie cities to show clips from movies, and teachers to distribute portions of newspaper articles. The reasoning behind the law is that the benefit to the public from such uses outweighs any harm to the copyright owner. Other situations in which copyrighted material may be used to a limited degree without fear of infringement include parody, reproduction by libraries, and making a single backup copy of a computer program or a digital music file for personal use.