@inbook{NBERc9626,
 Crossref = "NBERcost03-1",
 title = "Reflections on the Early Indicators Project.A Partial History",
 author = "Larry T. Wimmer",
 BookTitle = "Health and Labor Force Participation over the Life Cycle: Evidence from the Past",
 Publisher = "University of Chicago Press",
 pages = "1-10",
 year = "2003",
 month = "January",
 URL = "http://www.nber.org/chapters/c9626",
}
@book{NBERcost03-1,
 title = "Health and Labor Force Participation over the Life Cycle: Evidence from the Past",
 author = "Dora L. Costa",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2003",
 URL = "http://www.nber.org/books/cost03-1",
}