Pictured is an example of Part 3 of Form 3731/Form 3731 (SP) used as a history sheet. Form 3731/Form 3731 (SP) is generated when unidentified remittances are added to the URF. The form contains name and address, date of the letter, document locator number, date, and remarks. The bottom section of the form contains the date payment received, kind of payment, amount of payment, social security or employer identification number shown on payment.