United States. Bureau of Labor Statistics. "Occupational Wage Survey: Davenport-Rock Island-Moline, Iowa-Illinois, October 1960 : Bulletin of the United States Bureau of Labor Statistics, No. 1285-16," Occupational Wage Survey (December 1960). https://fraser.stlouisfed.org/title/4510/item/495861, accessed on January 25, 2025.