United States. Bureau of the Census. "Comparisons from Specific Peak and Trough Levels and Specific Trough Dates," in United States. Bureau of the Census. "July 1965," Business Conditions Digest (July 1965) : 72-72. https://fraser.stlouisfed.org/title/43/item/7217/toc/188761 , accessed on April 18, 2024.