APA aipamena

Gray, R. B. (1975). The agricultural tractor, 1855-1950. American Society of Agricultural Engineers.

Chicago Style aipamena

Gray, Roy Burton. The Agricultural Tractor, 1855-1950. Saint Joseph, Mich.: American Society of Agricultural Engineers, 1975.

MLA aipamena

Gray, Roy Burton. The Agricultural Tractor, 1855-1950. American Society of Agricultural Engineers, 1975.