@inbook{NBERc5072,
 Crossref = "NBERdiew08-1",
 title = "Re-Assessing the U.S. Quality Adjustment to Computer Prices: The Role of Durability and Changing Software",
 author = "Robert C. Feenstra and Christopher R. Knittel",
 BookTitle = "Price Index Concepts and Measurement",
 Publisher = "University of Chicago Press",
 pages = "129-160",
 year = "2009",
 month = "December",
 URL = "http://www.nber.org/chapters/c5072",
}
@book{NBERdiew08-1,
 title = "Price Index Concepts and Measurement",
 author = "W. Erwin Diewert and John S. Greenlees and Charles R. Hulten",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "2009",
 URL = "http://www.nber.org/books/diew08-1",
}