@inbook{NBERc10230,
 Crossref = "NBERlamo99-1",
 title = "Patents, Engineering Professionals, and the Pipelines of Innovation: The Internalization of Technical Discovery by Nineteenth-Century American Railroads  ",
 author = "Steven Usselman",
 BookTitle = "Learning by Doing in Markets, Firms, and Countries",
 Publisher = "University of Chicago Press",
 pages = "61-102",
 year = "1999",
 month = "January",
 URL = "http://www.nber.org/chapters/c10230",
}
@book{NBERlamo99-1,
 title = "Learning by Doing in Markets, Firms, and Countries",
 author = "Naomi R. Lamoreaux and Daniel M. G. Raff and Peter Temin",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "University of Chicago Press",
 year = "1999",
 URL = "http://www.nber.org/books/lamo99-1",
}