The bonds may be refunded in accordance with Article 6 (commencing with Section 16780) of Chapter 4 of Part 3 of Division 4 of Title 2 of the Government Code, which is a part of the State General Obligation Bond Law. Approval by the voters of the state for the issuance of the bonds described in this division includes the approval of the issuance of any other bonds issued to refund any bonds originally issued under this division or any previously issued refunding bonds.