Iowa State University. Cooperative Extension Service. Dairy Husbandry and Dairy Products Extension Service publications and records.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Iowa State University. Cooperative Extension Service. Dairy Husbandry and Dairy Products Extension Service Publications and Records.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Iowa State University. Cooperative Extension Service. Dairy Husbandry and Dairy Products Extension Service Publications and Records.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.