United States. Bureau of Labor Statistics. "Productivity and Costs in Selected Service-Providing and Mining Industries, 2002 : Productivity and Costs in Selected Service-Providing and Mining Industries, 2002, USDL 04-1061,"
Productivity and Costs by Industry
(June 16, 2004).
https://fraser.stlouisfed.org/title/9618/item/703977/content/pdf/prin_20040616, accessed on June 11, 2026.