Federal Reserve Bank of Chicago. "Information for Cash Agents of the First Class When Surrendering War Savings Certificates and Thrift Stamps of the 1919 Series for Cash Redemption, Circular no. 227" in Federal Reserve Bank of Chicago Bulletins and Circular Letters (December 30, 1919). https://fraser.stlouisfed.org/title/7180/item/655639, accessed on January 31, 2025.