@inbook{NBERc7056,
 Crossref = "NBERuniv65-2",
 title = "Innovation and Technical Change in the Railroad Industry",
 author = "Edwin Mansfield",
 BookTitle = "Transportation Economics",
 Publisher = "UMI",
 pages = "169-197",
 year = "1965",
 URL = "http://www.nber.org/chapters/c7056",
}
@book{NBERuniv65-2,
 title = "Transportation Economics",
 author = "Rendigs Fels, Chairman, Chairman, Universities-National Bureau Committee for Economic Research",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "UMI",
 year = "1965",
 URL = "http://www.nber.org/books/univ65-2",
}