Federal Reserve Bank of Chicago. "Information Re: Closing of Subscription Books : 2 1/2 Per Cent Treasury Bonds of 1967-72 (Additional Issue), and 2 Per Cent Treasury Bonds of 1951-55, Circular No. 617" in Federal Reserve Bank of Chicago Bulletins and Circular Letters (December 4, 1941). https://fraser.stlouisfed.org/title/7180/item/658186, accessed on February 17, 2025.