Helgeson, E. A. (1957). Methods of weed control. Food and Agriculture Organization of the United Nations.
芝加哥风格引文Helgeson, Earl A. Methods of Weed Control. Rome: Food and Agriculture Organization of the United Nations, 1957.
MLA引文Helgeson, Earl A. Methods of Weed Control. Food and Agriculture Organization of the United Nations, 1957.
警告：这些引文格式不一定是100％准确.