United States. Bureau of Labor Statistics. "Manufacturing Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Third Quarter 1993 [Revised]," Productivity and Costs (December 8, 1993) : 14-15. https://fraser.stlouisfed.org/title/131/item/55831/toc/472650 , accessed on April 26, 2024.