(a) At maturity pursuant to redemption provisions in the outstanding revenue bonds; or
(b) At any time before maturity if the holders of the outstanding revenue bonds consent or if the outstanding revenue bonds authorize redemption before maturity.
(2) ORS 777.560 to 777.590 apply to bonds authorized to be issued and sold under this section. [1955 c.423 §7; 1959 c.337 §6; 1965 c.223 §7; 1971 c.728 §90]