Não informado. (1919). Department circular. U.S. Department of Agriculture.
Chicagoスタイル(17版)引用形式Não informado. Department Circular. Washington: U.S. Department of Agriculture, 1919.
MLA(8版)引用形式Não informado. Department Circular. U.S. Department of Agriculture, 1919.
警告: この引用は必ずしも正確ではありません.