United States. Bureau of Labor Statistics. "Footnotes," in United States. Bureau of Labor Statistics. "Private Business, Nonfarm Business, and Manufacturing Sectors : Third Quarter 1979," Productivity and Costs (October 29, 1979) : 10-10. https://fraser.stlouisfed.org/title/131/item/55891/toc/495095 , accessed on April 19, 2024.