419
"Age Shall Not Wither Them," Economist, April 7, 2011.
420
"Researchers Find Risk-Taking Behavior Rises Until Age 50," University of Oregon, Media Relations, November 10, 2011, .
421
Самые значительные из них – Robert J. Gordon, Christina D. Romer, Robert E. Gallman, Paul David, Stanley L. Engerman, and John Kendrick.
422
Richard Sutch, ed., "National Income and Product," in Economic Structure and Performance, vol. 3 of Historical Statistics of the United States: Millennial Edition, ed. Susan B. Carter et al. (New York: Cambridge University Press, 2006).
