Não informado. (1949). Agricultural economics research. U.S. Department of Agriculture, Bureau of Agricultural Economics.
Chicago-Zitierstil (17. Ausg.)Não informado. Agricultural Economics Research. Washington: U.S. Department of Agriculture, Bureau of Agricultural Economics, 1949.
MLA-Zitierstil (8. Ausg.)Não informado. Agricultural Economics Research. U.S. Department of Agriculture, Bureau of Agricultural Economics, 1949.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.