United States. Dept. of Agriculture. Economic Research Service. (1991). World agriculture. U.S. Dept. of Agriculture, Economic Research Service.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)United States. Dept. of Agriculture. Economic Research Service. World Agriculture. Washington, D.C.: U.S. Dept. of Agriculture, Economic Research Service, 1991.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)United States. Dept. of Agriculture. Economic Research Service. World Agriculture. U.S. Dept. of Agriculture, Economic Research Service, 1991.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.