United States. Bureau of Labor Statistics , Nelson, Richard Rex , Chase, John H. and Pearson, Haney R. Collective Bargaining Agreements for Police and Firefighters : Bulletin of the United States Bureau of Labor Statistics, No. 1885 , Washington, D.C: U.S. Dept. of Labor, Bureau of Labor Statistics, 1976, https://fraser.stlouisfed.org/title/4671, accessed on October 3, 2024.