APA (7th ed.) Citation

U. S. Government Printing Office. (1961). 100=One hundred> GPO years, 1861-1961: A history of the United States public printing.

Chicago Style (17th ed.) Citation

U. S. Government Printing Office. 100=One Hundred> GPO Years, 1861-1961: A History of the United States Public Printing. [Washington], 1961.

MLA (9th ed.) Citation

U. S. Government Printing Office. 100=One Hundred> GPO Years, 1861-1961: A History of the United States Public Printing. 1961.