Federal Reserve Bank of Chicago. "June 1968," Business Conditions (Federal Reserve Bank of Chicago) (June 1968). https://fraser.stlouisfed.org/title/5562/item/540264, accessed on April 24, 2024.
Federal Reserve Bank of Chicago. "June 1968," Business Conditions (Federal Reserve Bank of Chicago) (June 1968). https://fraser.stlouisfed.org/title/5562/item/540264, accessed on April 24, 2024.