United States. Bureau of Labor Statistics. "Footnotes," in United States. Bureau of Labor Statistics. "Private Business, Nonfarm Business, and Manufacturing Sectors : Third Quarter 1978," Productivity and Costs (October 27, 1978) : 11-11. https://fraser.stlouisfed.org/title/131/item/55884/toc/495029 , accessed on April 25, 2024.