APA (7th ed.) Citation

United States. War Department. (1931). Duluth-Superior Harbor: Statistical report of marine commerce of Duluth, Minn., and Superior, Wis. for calendar year 1931. GPO.

Chicago Style (17th ed.) Citation

United States. War Department. Duluth-Superior Harbor: Statistical Report of Marine Commerce of Duluth, Minn., and Superior, Wis. for Calendar Year 1931. [Washington]: GPO, 1931.

MLA (9th ed.) Citation

United States. War Department. Duluth-Superior Harbor: Statistical Report of Marine Commerce of Duluth, Minn., and Superior, Wis. for Calendar Year 1931. GPO, 1931.