@inbook{NBERc7241,
 Crossref = "NBERgril92-1",
 title = "Purchased Services, Outsourcing, Computers, and Productivity in Manufacturing",
 author = "Donald Siegel and Zvi Griliches",
 BookTitle = "Output Measurement in the Service Sectors",
 Publisher = "University of Chicago Press",
 pages = "429-460",
 year = "1992",
 month = "January",
 URL = "http://www.nber.org/chapters/c7241",
}
@book{NBERgril92-1,
 title = "Output Measurement in the Service Sectors",
 author = "Zvi Griliches",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1992",
 URL = "http://www.nber.org/books/gril92-1",
}