United States. Bureau of Labor Statistics. "Nonfinancial Corporations," in United States. Bureau of Labor Statistics. "Second Quarter 1989 [Revised] : Business, Nonfarm Business, Manufacturing, and Nonfinancial Corporations," Productivity and Costs (September 6, 1989) : 11-11. https://fraser.stlouisfed.org/title/131/item/55975/toc/457706 , accessed on March 28, 2024.