@inbook{NBERc7849,
 Crossref = "NBERfree95-1",
 title = "Front matter, Differences and Changes in Wage Structures",
 author = "Richard B. Freeman and Lawrence F. Katz",
 BookTitle = "Differences and Changes in Wage Structures",
 Publisher = "University of Chicago Press",
 year = "1995",
 month = "January",
 URL = "http://www.nber.org/chapters/c7849",
}
@book{NBERfree95-1,
 title = "Differences and Changes in Wage Structures",
 author = "Richard B. Freeman and Lawrence F. Katz",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1995",
 URL = "http://www.nber.org/books/free95-1",
}