United States. Bureau of Labor Statistics. "Footnotes," in United States. Bureau of Labor Statistics. "Revised Second-Quarter [1988] Measures for Business, Nonfarm Business, and Manufacturing and Preliminary Measures for Nonfinancial Corporations," Productivity and Costs (September 1, 1988) : 12-12. https://fraser.stlouisfed.org/title/131/item/55808/toc/455367 , accessed on April 18, 2024.