@inbook{NBERc7080,
 Crossref = "NBERwise98-2",
 title = "2. What Is Technological Change?",
 author = "David M. Cutler and Mark B. McClellan",
 BookTitle = "Inquiries in the Economics of Aging",
 Publisher = "University of Chicago Press",
 pages = "51-81",
 year = "1998",
 month = "January",
 URL = "http://www.nber.org/chapters/c7080",
}
@book{NBERwise98-2,
 title = "Inquiries in the Economics of Aging",
 author = "David A. Wise",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1998",
 URL = "http://www.nber.org/books/wise98-2",
}