United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Annual Data for 1977," Productivity and Costs (February 28, 1978). https://fraser.stlouisfed.org/title/131/item/55882, accessed on April 25, 2024.
United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Annual Data for 1977," Productivity and Costs (February 28, 1978). https://fraser.stlouisfed.org/title/131/item/55882, accessed on April 25, 2024.