@techreport{NBERw7478,
 title = "150 Years of Patent Protection",
 author = "Josh Lerner",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "7478",
 year = "2000",
 month = "January",
 URL = "http://www.nber.org/papers/w7478",
 abstract = {This paper examines three sets of explanations for variations in the strength of patent protection across sixty countries and a 150-year period.  Wealthier nations are more likely to have patent systems, to allow patentees a longer time to put their patents into practice, and to ratify treaties assuring equal treatment of other nations.  But they are also likely to charge higher fees and limit patent protection in some important ways. Countries with democratic political institutions are consistently more likely to have patent protection appear to be determined by historical factors.  The origin of a country's commercial law appears particularly important in explaining the presence of restrictions on patentees' privileges and discriminatory provisions against foreign patentees.},
}