Federal Reserve Bank of Dallas. "U.S. Postal Service Money Orders, Circular No. 81-67," District Notices (Federal Reserve Bank of Dallas) (April 6, 1981). https://fraser.stlouisfed.org/title/5569/item/541250, accessed on January 21, 2019.
Changes Made to Both Domestic and Military Money Orders. Maximum Value Increased to $500. United States Postal Service Seal and Limitation Values No Longer Imprinted.