Cita APA (7a ed.)

Helgeson, E. A. (1957). Methods of weed control. Food and Agriculture Organization of the United Nations.

Cita Chicago Style (17a ed.)

Helgeson, Earl A. Methods of Weed Control. Rome: Food and Agriculture Organization of the United Nations, 1957.

Cita MLA (9a ed.)

Helgeson, Earl A. Methods of Weed Control. Food and Agriculture Organization of the United Nations, 1957.