United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Annual Data for 1980," Productivity and Costs (February 26, 1981). https://fraser.stlouisfed.org/title/131/item/55900, accessed on April 23, 2024.
United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Annual Data for 1980," Productivity and Costs (February 26, 1981). https://fraser.stlouisfed.org/title/131/item/55900, accessed on April 23, 2024.