@inbook{NBERc9520,
 Crossref = "NBERunkn39-1",
 title = "Preface, table of contents",
 author = "Conference on Research in National Income and Wealth",
 BookTitle = "Studies in Income and Wealth, Volume 3",
 Publisher = "NBER",
 pages = "-20-1",
 year = "1939",
 URL = "http://www.nber.org/chapters/c9520",
}
@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",
}