Dyfyniad APA
Gardner, B. L. (2006). American agriculture in the twentieth century: How it flourished and what it cost. Harvard University Press.
Dyfyniad Arddull Chicago
Gardner, Bruce L. American Agriculture in the Twentieth Century: How It Flourished and What It Cost. Cambridge, MA: Harvard University Press, 2006.
Dyfyniad MLA
Gardner, Bruce L. American Agriculture in the Twentieth Century: How It Flourished and What It Cost. Harvard University Press, 2006.
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