Não informado. (1919). Department circular. U.S. Department of Agriculture.
Style de citation Chicago (17e éd.)Não informado. Department Circular. Washington: U.S. Department of Agriculture, 1919.
Style de citation MLA (8e éd.)Não informado. Department Circular. U.S. Department of Agriculture, 1919.
Attention : ces citations peuvent ne pas être correctes à 100%.