1. Rockey, S. Age Distribution of NIH Principal Investigators and Medical School Faculty (13 February 2012); available at
http://go.nature.com/2uzqca
2. Jones, B. F. Rev. Econ. Stud. 76, 283–317 (2009).
3. Cohen, J. & Dupas, P. Q. J. Econ. 125, 1–45 (2010).
4. Banerjee, A. V. & Duflo, E. Poor Economics: A Radical Rethinking of the Way to Fight Global Poverty (PublicAffairs, 2011).