The story of the reaper is told in: Herbert N. Casson, "Cyrus Hall McCormick; His Life and Work" (1909), and "The Romance of the Reaper" (1908), and Merritt F. Miller, "Evolution of Reaping Machines" (1902), U. S. Experiment Stations Office, Bulletin 103. Other farm inventions are covered in: William Macdonald, "Makers of Modern Agriculture" (1913); Emile Guarini, "The Use of Electric Power in Plowing" in The "Electrical Review", vol. XLIII; A. P. Yerkes, "The Gas Tractor in Eastern Farming" (1918), U. S. Department of Agriculture, Farmer's Bulletin 1004; and Herbert N. Casson and others, "Horse, Truck and Tractor; the Coming of Cheaper Power for City and Farm" (1913).