Não informado. (1949). Agricultural economics research. U.S. Department of Agriculture, Bureau of Agricultural Economics.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Agricultural Economics Research. Washington: U.S. Department of Agriculture, Bureau of Agricultural Economics, 1949.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Agricultural Economics Research. U.S. Department of Agriculture, Bureau of Agricultural Economics, 1949.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.