United States. Bureau of Labor Statistics. "Chart - Unit Costs, Unit Profits and Prices in Nonfinancial Corporations," in United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Third Quarter 1980," Productivity and Costs (November 26, 1980) : 14-14. https://fraser.stlouisfed.org/title/131/item/56000/toc/437687 , accessed on April 27, 2024.