Não informado. (1968). Foreign agriculture. U.S. Department of Agriculture, Foreign Agricultural Service.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Foreign Agriculture. Washington: U.S. Department of Agriculture, Foreign Agricultural Service, 1968.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Foreign Agriculture. U.S. Department of Agriculture, Foreign Agricultural Service, 1968.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.