Não informado. (1931). Cotton situation. U.S. Department of Agriculture, Bureau of Agricultural Economics.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Cotton Situation. Washington: U.S. Department of Agriculture, Bureau of Agricultural Economics, 1931.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Cotton Situation. U.S. Department of Agriculture, Bureau of Agricultural Economics, 1931.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.