@inbook{NBERc5578,
 Crossref = "NBERunkn57-1",
 title = "Introduction  ",
 author = "Franco Modigliani",
 BookTitle = "Problems of Capital Formation: Concepts, Measurement, and Controlling Factors",
 Publisher = "NBER",
 pages = "3-9",
 year = "1957",
 URL = "http://www.nber.org/chapters/c5578",
}
@book{NBERunkn57-1,
 title = "Problems of Capital Formation: Concepts, Measurement, and Controlling Factors",
 author = "Conference on Research in Income and Wealth",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1957",
 URL = "http://www.nber.org/books/unkn57-1",
}