Hughes, J. R. T. (1986). The vital few: The entrepreneur and American economic progress (Expanded ed.). Oxford University Press.

Hughes, Jonathan R. T. The Vital Few: The Entrepreneur and American Economic Progress. Expanded ed. New York: Oxford University Press, 1986.

Hughes, Jonathan R. T. The Vital Few: The Entrepreneur and American Economic Progress. Expanded ed. Oxford University Press, 1986.