@techreport{NBERw12025,
 title = "Geographic Spillover of Unionism",
 author = "Thomas J. Holmes",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "12025",
 year = "2006",
 month = "February",
 URL = "http://www.nber.org/papers/w12025",
 abstract = {Unionism in the United States is contagious; it spills out of coal mines and steel mills into other establishments in the neighborhood, like hospitals and supermarkets. The geographic spillover of unionism is documented here using a newly constructed establishment level data on unionism that is rich in geographic detail. A strong connection is found between unionism of health care establishments today and proximity to unionized coal mines and steel mills from the 1950s.},
}