@techreport{NBERw12999,
 title = "Internal Increasing Returns to Scale and Economic Growth",
 author = "John A. List and Haiwen Zhou",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "12999",
 year = "2007",
 month = "March",
 URL = "http://www.nber.org/papers/w12999",
}