Federal Reserve Bank of Chicago. "May 1971," Business Conditions (Federal Reserve Bank of Chicago) (May 1971). https://fraser.stlouisfed.org/title/5562/item/540299, accessed on April 19, 2024.
Federal Reserve Bank of Chicago. "May 1971," Business Conditions (Federal Reserve Bank of Chicago) (May 1971). https://fraser.stlouisfed.org/title/5562/item/540299, accessed on April 19, 2024.