United States. Bureau of Labor Statistics. "Durable Manufacturing Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Second Quarter 2000 [Preliminary]," Productivity and Costs (August 8, 2000) : 16-16. https://fraser.stlouisfed.org/title/131/item/55936/toc/444843 , accessed on April 25, 2024.