@techreport{NBERw12669,
 title = "Minerva Unbound: Knowledge Stocks, Knowledge Flows and New Knowledge Production",
 author = "Lynne G. Zucker and Michael R. Darby and Jonathan Furner and Robert C. Liu and Hongyan Ma",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "12669",
 year = "2006",
 month = "November",
 URL = "http://www.nber.org/papers/w12669",
}