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The influence of machinery on agricultural conditions in North America
Riddell, W. A., (1926)
Technological change in agriculture
Nevel, Robert O., (1969)
The farm maschinery and equipment industry : its changing structure and performance
Nelson jr., Paul E., (1970)
Farm machinery : use, depreciation, and replacement
Parsons, Merton S., (1960)
Extent and cost of spraying and dusting on farms, 1952
Brodell, Albert P., (1955)
Extent of spraying and dusting on farms, 1958, with comparisons
Strickler, Paul E., (1962)