Clark, G. (1990). Outline of the U S Economy. United States Department of State.
Chicago-referens (17:e uppl.)Clark, George. Outline of the U S Economy. United States Department of State, 1990.
MLA-referens (9:e uppl.)Clark, George. Outline of the U S Economy. United States Department of State, 1990.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.