@inbook{NBERc2757,
 Crossref = "NBERwolm36-1",
 title = "Centers of Unionism",
 author = "Leo Wolman",
 BookTitle = "Ebb and Flow in Trade Unionism",
 Publisher = "NBER",
 pages = "84-109",
 year = "1936",
 URL = "http://www.nber.org/chapters/c2757",
}
@book{NBERwolm36-1,
 title = "Ebb and Flow in Trade Unionism",
 author = "Leo Wolman",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1936",
 URL = "http://www.nber.org/books/wolm36-1",
}