APA (7th ed.) Citation

United States. Army Map Service. (1948). Portugal 1: 50,000.

Chicago Style (17th ed.) Citation

United States. Army Map Service. Portugal 1: 50,000. Washington, 1948.

MLA (9th ed.) Citation

United States. Army Map Service. Portugal 1: 50,000. 1948.

Warning: These citations may not always be 100% accurate.