Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "Estimated Foreign Holdings of Marketable U.S. Government Bonds and Notes," in Board of Governors of the Federal Reserve System (U.S.), 1935- and Federal Reserve Board, 1914-1935. "September 1968," Federal Reserve Bulletin (September 1968) : 147-147. https://fraser.stlouisfed.org/title/62/item/21405/toc/65228 , accessed on April 17, 2024.