Two examples of material in the public domain are [[United States]] government works and writings for which their [[copyright]] has expired. Generally anything published before 1923 cannot have copyright protection and is in the public domain (''in the United States''). | Two examples of material in the public domain are [[United States]] government works and writings for which their [[copyright]] has expired. Generally anything published before 1923 cannot have copyright protection and is in the public domain (''in the United States''). |