Não informado. (1980). Soil and water conservation news. U.S. Department of Agriculture, Soil Conservation Service.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিNão informado. Soil and Water Conservation News. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1980.
M.L.A (8 ম সংস্করণ) উদ্ধৃতিNão informado. Soil and Water Conservation News. U.S. Department of Agriculture, Soil Conservation Service, 1980.
সতর্কবাণী: সাইটেশন সবসময় 100% নির্ভুল হতে পারে না.