United States. Bureau of Labor Statistics. "Business Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Second Quarter 1994 [Preliminary]," Productivity and Costs (August 9, 1994) : 18-18. https://fraser.stlouisfed.org/title/131/item/55916/toc/486094 , accessed on June 27, 2024.