United States. Bureau of Labor Statistics. "Unit Costs, Unit Profits and Prices In Nonfinancial Corporations," in United States. Bureau of Labor Statistics. "Nonfinancial Corporate Sector : Third Quarter 1978," Productivity and Costs (November 29, 1978) : 18-18. https://fraser.stlouisfed.org/title/131/item/55885/toc/495035 , accessed on April 26, 2024.