Não informado. (1937). Foreign agriculture. U.S. Department of Agriculture, Foreign Agricultural Service.
Citação do estilo Chicago (17ª ed.)Não informado. Foreign Agriculture. Washington: U.S. Department of Agriculture, Foreign Agricultural Service, 1937.
Citação MLA (8ª ed.)Não informado. Foreign Agriculture. U.S. Department of Agriculture, Foreign Agricultural Service, 1937.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.