@inbook{NBERc4551,
 Crossref = "NBERbrow08-1",
 title = "Demographic Change, Relative Factor Prices, International Capital Flows, and Their Differential Effects on the Welfare of Generations ",
 author = "Alexander Ludwig and Dirk Krüger and Axel Börsch-Supan",
 BookTitle = "Social Security Policy in a Changing Environment",
 Publisher = "University of Chicago Press",
 pages = "385-414",
 year = "2009",
 month = "June",
 URL = "http://www.nber.org/chapters/c4551",
}
@book{NBERbrow08-1,
 title = "Social Security Policy in a Changing Environment",
 author = "Jeffrey R. Brown and Jeffrey B. Liebman and David A. Wise",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2009",
 URL = "http://www.nber.org/books/brow08-1",
}