@techreport{NBERw5712,
 title = "Flows of Knowledge from Universities and Federal Labs: Modeling the Flowof Patent Citations Over Time and Across Institutional and Geographic Boundari",
 author = "Adam B. Jaffe and Manuel Trajtenberg",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "5712",
 year = "1996",
 month = "August",
 URL = "http://www.nber.org/papers/w5712",
 abstract = {The extent to which new technological knowledge flows across institutional and national boundaries is a question of great importance for public policy and the modeling of economic growth. This paper develops a model of the process generating subsequent citations to patents as a lens for viewing knowledge diffusion. We find that the probability of patent citation over time after a patent is granted fits well to a double-exponential function that can be interpreted as the mixture of diffusion and obsolescence functions.  The results indicate that diffusion is geographically localized.  Controlling for other factors, within-country citations are more numerous and come more quickly than those that cross country boundaries.},
}