APA (7th ed.) Citation

United States. National Archives and Records Administration & United States. Bureau of the Census. (2012). 1940 census: Official 1940 census website. National Archives.

Chicago Style (17th ed.) Citation

United States. National Archives and Records Administration and United States. Bureau of the Census. 1940 Census: Official 1940 Census Website. [Washington, D.C.]: National Archives, 2012.

MLA (8th ed.) Citation

United States. National Archives and Records Administration and United States. Bureau of the Census. 1940 Census: Official 1940 Census Website. National Archives, 2012.

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