Não informado. (1987). The Journal of Agricultural Economics Research. U.S. Department of Agriculture.
Chicago-Zitierstil (17. Ausg.)Não informado. The Journal of Agricultural Economics Research. Washington: U.S. Department of Agriculture, 1987.
MLA-Zitierstil (8. Ausg.)Não informado. The Journal of Agricultural Economics Research. U.S. Department of Agriculture, 1987.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.