Não informado. (1957). Foreign agriculture circular. U.S. Department of Agriculture, Foreign Agricultural Service.
Chicago-Zitierstil (17. Ausg.)Não informado. Foreign Agriculture Circular. Washington: U.S. Department of Agriculture, Foreign Agricultural Service, 1957.
MLA-Zitierstil (8. Ausg.)Não informado. Foreign Agriculture Circular. U.S. Department of Agriculture, Foreign Agricultural Service, 1957.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.