APA (7e ed.) Bronvermelding

Não informado. (2004). Ers. U.S. Department of Agriculture, Economic Research Service.

Chicago (17e ed.) Bronvermelding

Não informado. Ers. Washington: U.S. Department of Agriculture, Economic Research Service, 2004.

MLA (8e ed.) Bronvermelding

Não informado. Ers. U.S. Department of Agriculture, Economic Research Service, 2004.

Let op: Deze citaties zijn niet altijd 100% accuraat.