@inbook{NBERc2563,
 Crossref = "NBERlich59-1",
 title = "Introduction and Plan of the Study",
 author = "Robert M. Lichtenberg",
 BookTitle = "The Role of Middleman Transactions in World Trade",
 Publisher = "NBER",
 pages = "1-8",
 year = "1959",
 URL = "http://www.nber.org/chapters/c2563",
}
@book{NBERlich59-1,
 title = "The Role of Middleman Transactions in World Trade",
 author = "Robert M. Lichtenberg",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1959",
 URL = "http://www.nber.org/books/lich59-1",
}