Smith, J. R. (1929). Tree crops: A permanent agriculture. Harcourt, Brace.
Cita Chicago (17th ed.)Smith, J. Russell. Tree Crops: A Permanent Agriculture. New York: Harcourt, Brace, 1929.
Cita MLA (9th ed.)Smith, J. Russell. Tree Crops: A Permanent Agriculture. Harcourt, Brace, 1929.
Atenció: Aquestes cites poden no estar 100% correctes.