Refunding bonds; detail; form.

Refunding bonds shall bear interest payable annually or semiannually, and the refunding bonds shall be due and payable either as term or serial bonds as determined by the board; provided that no refunding bond shall mature more than twenty-five years from the date of the refunding bond. The form and terms of the refunding bonds, including provisions for their payment and redemption, shall be determined by the board. If the board so determines in the authorizing resolution, the refunding bonds may be redeemable prior to maturity without or with the payment of a premium, which may be in any amount determined by the board.