It is an anonymous, pseudonymous or posthumous work and 50 years have passed since the date of its publication
It is a photographic work, and 25 years have passed since the date of its publication
It is another kind of work, and 50 years have passed since the year of death of the author (or last-surviving author)
It is an "official act of authority" and ineligible for copyright protection; however "literary, artistic, or scientific publications produced by the authorities" are copyrighted by the government
