@inbook{NBERc6066,
 Crossref = "NBERbres96-1",
 title = "The Welfare Implications of Invention",
 author = "Walter Y. Oi",
 BookTitle = "The Economics of New Goods",
 Publisher = "University of Chicago Press",
 pages = "109-142",
 year = "1996",
 month = "January",
 URL = "http://www.nber.org/chapters/c6066",
}
@book{NBERbres96-1,
 title = "The Economics of New Goods",
 author = "Timothy F. Bresnahan and Robert J. Gordon",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1997",
 URL = "http://www.nber.org/books/bres96-1",
}