United States. World Agricultural Outlook Board, United States. Foreign Agricultural Service, & United States. Foreign Agricultural Service. Foreign Production Estimates Division. (1987). World crop production. U.S. Dept. of Agriculture, Foreign Agricultural Service.
芝加哥风格引文United States. World Agricultural Outlook Board, United States. Foreign Agricultural Service, 与 United States. Foreign Agricultural Service. Foreign Production Estimates Division. World Crop Production. [Washington, D.C.]: U.S. Dept. of Agriculture, Foreign Agricultural Service, 1987.
MLA引文United States. World Agricultural Outlook Board, et al. World Crop Production. U.S. Dept. of Agriculture, Foreign Agricultural Service, 1987.
警告：这些引文格式不一定是100％准确.