@inbook{NBERc1707,
 Crossref = "NBERtroy65-1",
 title = "Introduction to "Trade Union Membership, 1897-1962"",
 author = "Leo Troy",
 BookTitle = "Trade Union Membership, 1897-1962",
 Publisher = "NBER",
 pages = "1-10",
 year = "1965",
 URL = "http://www.nber.org/chapters/c1707",
}
@book{NBERtroy65-1,
 title = "Trade Union Membership, 1897-1962",
 author = "Leo Troy",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1965",
 URL = "http://www.nber.org/books/troy65-1",
}