The term 'PAPER MONEY SOURCE' can be solved by the three-letter acronym ADS. ADS stands for 'Authorized Dealer System, ' which is a system used by the United States Treasury to distribute paper money. This system is used to ensure that the paper money is distributed in an orderly and secure manner, and it is also used to track the circulation of paper money. The Authorized Dealer System is used by banks, businesses, and other financial institutions to obtain paper money from the United States Treasury.