Tontz, R. L. (1966). Foreign agricultural trade: Selected readings ([1st ed.].). Iowa State University Press.
Lua i Stíl Chicago (17ú heag.)Tontz, Robert L. Foreign Agricultural Trade: Selected Readings. [1st ed.]. Ames: Iowa State University Press, 1966.
Lua MLA (9ú heag.)Tontz, Robert L. Foreign Agricultural Trade: Selected Readings. [1st ed.]. Iowa State University Press, 1966.
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