Section 381.237 - Issuance of refunding revenue bonds(1) Any county, city, town or port mentioned in ORS 381.205, heretofore or hereafter issuing its revenue bonds under ORS 381.205 to 381.314, may thereafter issue and sell its refunding revenue bonds for the purpose of refinancing and redeeming such outstanding revenue bonds at maturity pursuant to redemption provisions, or at any time before maturity either with the consent of the holders thereof or if the bonds shall so provide.(2) In determining the amount of refunding revenue bonds to be issued: (a) Due credit shall be given for the application of any sinking funds available for the payment of such outstanding revenue bonds, less appropriate reserves deemed necessary to be retained on account of the refunding revenue bonds.(b) There may be included in determining such amount the costs and expenses in connection with the issuance and sale of the refunding revenue bonds, the premium, if any, to be paid on any of the revenue bonds to be refunded, the unpaid interest to accrue on the revenue bonds to be refunded prior to the retirement thereof, and the cost of any improvements to the bridge then determined by the governing authority to be necessary or advisable.(3) The refunding revenue bonds shall be secured in the same manner and be payable from the same source as the revenue bonds refinanced and redeemed as may be otherwise provided in the resolution adopted by the governing authority of the county, city, town or port, but in no event shall such refunding revenue bonds constitute general obligations of the county, city, town or port, nor an indebtedness or liability within the meaning of any constitutional limitation or provision.