"Growth Cycles," with George Evans and Seppo Honkapojha (American Economic Review, June 1998)
"Science, Economic Growth and Public Policy" (in B. Smith and C. Barfield, eds., Technology, R&D, and the Economy, Brookings Institution and American Enterprise Institute, 1996)
"Endogenous Technological Change" (Journal of Political Economy, October 1990)
"Increasing Returns and Long Run Growth" (Journal of Political Economy, October 1986).