(1990), pp. 50-68.
American Economic Review, Vol. 78, No. 3. (June 1988), pp. 307-317.
American Economic Review, Vol. 56 (May 1966), pp. 62-68.
The Belnap Press of Harvard University Press (1982)
Research Policy, Vol. 16 (1987), pp. 87-99.
American Economic Review, Vol. 67, No. 3. (June 1977), pp. 297-308.
Review of Economic Studies, Vol. 29 (June 1962), pp. 155--173.
Journal of Political Economy, Vol. 98 (October 1990a), pp. s71-102.
Journal of Political Economy, Vol. 99 (June 1991), pp. 500-521.
American Economic Review, Vol. 56 (May 1966), pp. 69-75.
Journal of Economic Literature, Vol. 25, No. 2. (June 1987), pp. 649-698.
Journal of Monetary Economics, Vol. 22, No. 1. (June 1988), pp. 3-42.
Journal of Ecomomic Perspectives, Vol. 2, No. 4. (1988), pp. 9-21.
American Ecomomic Review Papers and Proceedings, Vol. 80, No. 2. (May 1992), pp. 415-421.
Journal of Economic Dynamics and Control, Vol. 21, No. 1. (January 1997), pp. 1-22.
Journal of Economic Dynamics and Control, Vol. 21, No. 1. (January 1997), pp. 75-114.
Journal of Economic Perspectives, Vol. 8, No. 1. (winter 1994), pp. 23-44.
Journal of Economic Perspectives, Vol. 8, No. 1. (winter 1994), pp. 3-22.
Journal of Economic Perspectives, Vol. 8, No. 1. (winter 1994), pp. 55-72.
Economic Journal, Vol. 102, No. 412. (May 1992), pp. 611-621.
Journal of Economic Perspectives, Vol. 8, No. 1. (winter 1994), pp. 45-54.
Quarterly Journal of Economics, Vol. 114, No. 1. (February 1999), pp. 83-116.