United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE. U.S.G.P., 1967. (AGRICULTURE HANDBOOK NO. 344).
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.