Smith, J. R. (1929). Tree crops: A permanent agriculture. Harcourt, Brace.
Lua i Stíl Chicago (17ú heag.)Smith, J. Russell. Tree Crops: A Permanent Agriculture. New York: Harcourt, Brace, 1929.
Lua MLA (9ú heag.)Smith, J. Russell. Tree Crops: A Permanent Agriculture. Harcourt, Brace, 1929.
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