Federal Reserve Bank of Chicago. "January 1968," Business Conditions (Federal Reserve Bank of Chicago) (January 1968). https://fraser.stlouisfed.org/title/5562/item/540259, accessed on April 28, 2024.
Federal Reserve Bank of Chicago. "January 1968," Business Conditions (Federal Reserve Bank of Chicago) (January 1968). https://fraser.stlouisfed.org/title/5562/item/540259, accessed on April 28, 2024.