United States. Bureau of Labor Statistics. "Nonfarm Business Sector," in United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Third Quarter 1980," Productivity and Costs (November 26, 1980) : 5-5. https://fraser.stlouisfed.org/title/131/item/56000/toc/437694 , accessed on May 1, 2024.