@inbook{NBERc9525,
 Crossref = "NBERunkn39-1",
 title = "Three Estimates of the Value of the Nation's Output of Commodities and Services: A Comparison",
 author = "Clark Warburton",
 BookTitle = "Studies in Income and Wealth, Volume 3",
 Publisher = "NBER",
 pages = "317-398",
 year = "1939",
 URL = "http://www.nber.org/chapters/c9525",
}
@book{NBERunkn39-1,
 title = "Studies in Income and Wealth, Volume 3",
 author = "nference on Research in National Income and Wealth",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1939",
 URL = "http://www.nber.org/books/unkn39-1",
}