Federal Reserve Bank of Chicago. "April 1961," Business Conditions (Federal Reserve Bank of Chicago) (April 1961). https://fraser.stlouisfed.org/title/5562/item/540178, accessed on May 1, 2024.
Federal Reserve Bank of Chicago. "April 1961," Business Conditions (Federal Reserve Bank of Chicago) (April 1961). https://fraser.stlouisfed.org/title/5562/item/540178, accessed on May 1, 2024.