United States. Bureau of Labor Statistics. "Durable Manufacturing Sector - Appendix - Quarterly Data," in United States. Bureau of Labor Statistics. "Second Quarter 1994 [Preliminary]," Productivity and Costs (August 9, 1994) : 21-21. https://fraser.stlouisfed.org/title/131/item/55916/toc/486090 , accessed on June 29, 2024.