Federal Reserve Bank of Dallas. "Expansion Book-Entry Procedure for Treasury Securities, Circular No. 69-202," District Notices (Federal Reserve Bank of Dallas) (September 1, 1969). https://fraser.stlouisfed.org/title/5569/item/544218, accessed on August 16, 2018.
Expansion Book-entry Procedure for Treasury Securities; Subpart O Treasury Department Circular No. 300; Fiscal Agency Operating Circular No. 3; Bulletin No. 7