Tontz, R. L. (1966). Foreign agricultural trade: Selected readings ([1st ed.].). Iowa State University Press.
Παραπομπή σε μορφή Chicago (17η εκδ.)Tontz, Robert L. Foreign Agricultural Trade: Selected Readings. [1st ed.]. Ames: Iowa State University Press, 1966.
Παραπομπή σε μορφή MLA (9th εκδ.)Tontz, Robert L. Foreign Agricultural Trade: Selected Readings. [1st ed.]. Iowa State University Press, 1966.