Helgeson, E. A. (1957). Methods of weed control. Food and Agriculture Organization of the United Nations.
Chicago-čujuhus (17. p.)Helgeson, Earl A. Methods of Weed Control. Rome: Food and Agriculture Organization of the United Nations, 1957.
MLA-čujuhus (9. p.)Helgeson, Earl A. Methods of Weed Control. Food and Agriculture Organization of the United Nations, 1957.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.