United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE.
芝加哥风格引文United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE. U.S.G.P., 1967. (AGRICULTURE HANDBOOK NO. 344).
MLA引文United States. DEPARTMENT OF AGRICULTURE. ECONOMIC RESEARCH SERVICE. WORLDWIDE USE OF AIRPHOTOS IN AGRICULTURE.
警告：这些引文格式不一定是100％准确.