@techreport{NBERr1265,
 title = "Patent Renewal Data",
 author = "Ariel Pakes and Margaret Simpson",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Reprint Series",
 number = "1265",
 year = "1989",
 month = "September",
 URL = "http://www.nber.org/papers/r1265",
 abstract = {},
}