@techreport{NBERw12499,
 title = "A Conceptual World: Why the Art of the Twentieth Century is So Different From the Art of All Earlier Centuries",
 author = "David W. Galenson",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "12499",
 year = "2006",
 month = "August",
 URL = "http://www.nber.org/papers/w12499",
}