§4332. Amount, maturity and interest rate of bonds; use of proceeds
Any bonds issued under the provisions of this Sub-part shall not exceed in principal the amount then outstanding and unpaid of the original bond issue sought to be refunded, shall become due and payable in annual installments beginning not more than one year after the date of issuance, and run for a period of not more than twenty years, shall bear a maximum rate of interest not to exceed the rate of such original issue and shall not be sold for less than par and accrued interest. The proceeds of the bonds shall not be used for any purpose other than the payment and retirement of the outstanding amount of the original bond issue sought to be refunded.