García, Jorge Luis, James J. Heckman, Duncan Ermini Leaf, and María José Prados (2017). “Quantifying the Life-Cycle Benefits of a Prototypical Early Childhood Program,” NBER Working 6/8  BIS central bankers' speeches  Paper Series 23479. Cambridge, Mass. : National Bureau of Economic Research, June. Gordon, Robert (2014). “The demise of US economic growth: Restatement, rebuttal, and reflections,” NBER Working Paper Series 19895.
Cambridge, Mass. : National Bureau of Economic Research, November. Mohnen, Pierre, and Bronwyn H. Hall (2013). “Innovation and Productivity: An Update," Eurasian Business Review, vol. 3 (Spring), pp. 47–65. Mokyr, Joel (2014). “Secular Stagnation? Not in Your Life,” in Coen Teulings and Richard Baldwin, eds., Secular Stagnation: Facts, Causes, and Cures. London: CEPR Press, pp. 83–89. Pinto, Eugenio P., and Stacey Tevlin (2014).