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The cost and utilization of power on farms where tractors are owned : 286 farms - Ohio, Indiana, Illinois - 1920
Tolley, Howard Ross, (1921)
Cost of using tractors on corn-belt farms
Reynoldson, Le Roy August, (1922)
Harvesting small grain, soybeans, and clover in the corn belt with combines, and binders
Reynoldson, Le Roy August, (1931)