50 
    
    Там же, 166.
                51 
    
    George Rogers Taylor, The Transportation Revolution 1815–1860 (New York: M. E. Sharpe, 1951), 15–17.
                52 
    
    Там же, 132–133.
                53 
    
    Greene, Horses at Work, 52.
                54 
    
    Louis Cain, ed., "Transportation", Economic Sectors, vol. 4 of Historical Statistics of the United States: Millennial Edition, 762.
                55 
    
    Greene, Horses at Work, 78.
                56 
    
    Daniel Walker Howe, What Hath God Wrought: The Transformation of America, 1815–1848 (Oxford: Oxford University Press, 2007), 214.
                57 
    
    Cain, "Transportation", Economic Sectors, vol. 4 of Historical Statistics of the United States: Milliennial Edition, 770.
                58 
    
    Там же.
                59 
    
    Albert Fishlow, American Railroads and the Transformation of the Antebellum Economy (Cambridge, MA: Harvard University Press, 1965); Robert Fogel, Railroads and American Economic Growth (Baltimore: Johns Hopkins University Press, 1964).