@inbook{NBERc5221,
 Crossref = "NBERunkn64-3",
 title = "Appendix II-N: Service Industries",
 author = "Joel Popkin",
 BookTitle = "Measuring the Nation's Wealth",
 Publisher = "",
 pages = "767-790",
 year = "1964",
 URL = "http://www.nber.org/chapters/c5221",
}
@book{NBERunkn64-3,
 title = "Measuring the Nation's Wealth",
 author = "Wealth Inventory Planning Study",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "",
 year = "1964",
 URL = "http://www.nber.org/books/unkn64-3",
}