United States. Bureau of Labor Statistics. "Durable Manufacturing Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Second Quarter 2002 [Preliminary]," Productivity and Costs (August 9, 2002) : 19-19. https://fraser.stlouisfed.org/title/131/item/55946/toc/447219 , accessed on May 1, 2024.