Παραπομπή σε μορφή APA (7η εκδ.)

Whitman, R. B. (1920). Tractor principles: The action, mechanism, handling, care, maintenance and repair of the gas engine tractor. D. Appleton and Co..

Παραπομπή σε μορφή Chicago (17η εκδ.)

Whitman, Roger B. Tractor Principles: The Action, Mechanism, Handling, Care, Maintenance and Repair of the Gas Engine Tractor. New York, London: D. Appleton and Co., 1920.

Παραπομπή σε μορφή MLA (8th εκδ.)

Whitman, Roger B. Tractor Principles: The Action, Mechanism, Handling, Care, Maintenance and Repair of the Gas Engine Tractor. D. Appleton and Co., 1920.