@inbook{NBERc5901,
 Crossref = "NBERwolm24-1",
 title = "Chapter II. Changes in Union Membership, 1880-1923",
 author = "Leo Wolman",
 BookTitle = "The Growth of American Trade Unions, 1880-1923",
 Publisher = "NBER",
 pages = "29-66",
 year = "1924",
 URL = "http://www.nber.org/chapters/c5901",
}
@book{NBERwolm24-1,
 title = "The Growth of American Trade Unions, 1880-1923",
 author = "Leo Wolman",
 institution = "National Bureau of Economic Research",
 type = "Book",
 publisher = "NBER",
 year = "1924",
 URL = "http://www.nber.org/books/wolm24-1",
}