United States. Bureau of Labor Statistics. "Footnotes," in United States. Bureau of Labor Statistics. "Business, Nonfarm Business, and Manufacturing Sectors : Second Quarter 1983," Productivity and Costs (July 29, 1983) : 12-12. https://fraser.stlouisfed.org/title/131/item/55972/toc/450403 , accessed on April 25, 2024.