Não informado. Extension Folder. North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. Extension Folder. Raleigh, NC: North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. Extension Folder. North Carolina State College of Agriculture and Engineering, Agricultural Extension Service.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.