APA (7th ed.) Citation

United States. Postmaster General. (1930). C.O.D. tags must be legibly completed. U.S. GPO.

Chicago Style (17th ed.) Citation

United States. Postmaster General. C.O.D. Tags Must Be Legibly Completed. Washington: U.S. GPO, 1930.

MLA (9th ed.) Citation

United States. Postmaster General. C.O.D. Tags Must Be Legibly Completed. U.S. GPO, 1930.