United States. Bureau of Labor Statistics. "Union Wages and Hours: Local Truckdrivers and Helpers, July 1, 1969 : Bulletin of the United States Bureau of Labor Statistics, No. 1669," Union Wages and Hours : Local Truckdrivers and Helpers (1970). https://fraser.stlouisfed.org/title/3960/item/498652, accessed on January 30, 2025.