@inbook{NBERc1139,
 Crossref = "NBERkend68-1",
 title = "Sector Changes in Unit Labor Costs",
 author = "Leon Greenberg and Jerome A. Mark",
 BookTitle = "The Industrial Composition of Income and Product",
 Publisher = "UMI",
 pages = "103-150",
 year = "1968",
 URL = "http://www.nber.org/chapters/c1139",
}
@book{NBERkend68-1,
 title = "The Industrial Composition of Income and Product",
 author = "John W. Kendrick",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "UMI",
 year = "1968",
 URL = "http://www.nber.org/books/kend68-1",
}