United States. Bureau of Labor Statistics. "Nonfarm Business Sector," in United States. Bureau of Labor Statistics. "Revised First-Quarter [1987] Measures for Business, Nonfarm Business, and Manufacturing and Preliminary Measures for Nonfinancial Corporations," Productivity and Costs (June 2, 1987) : 8-8. https://fraser.stlouisfed.org/title/131/item/55802/toc/452376 , accessed on April 19, 2024.