@inbook{NBERc9770,
 Crossref = "NBERunkn52-1",
 title = "Directions of Further Inquiry",
 author = "Simon Kuznets",
 BookTitle = "Studies in Income and Wealth, Volume 15",
 Publisher = "NBER",
 pages = "201-214",
 year = "1952",
 URL = "http://www.nber.org/chapters/c9770",
}
@book{NBERunkn52-1,
 title = "Studies in Income and Wealth, Volume 15",
 author = "Conference on Research in Income and Wealth",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1952",
 URL = "http://www.nber.org/books/unkn52-1",
}