Não informado. (1980). Soil and water conservation news. U.S. Department of Agriculture, Soil Conservation Service.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. Soil and Water Conservation News. Washington: U.S. Department of Agriculture, Soil Conservation Service, 1980.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. Soil and Water Conservation News. U.S. Department of Agriculture, Soil Conservation Service, 1980.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.