Cal. Elec. Code § 19264

Any bonds issued and sold pursuant to this article may be refunded in accordance with Article 6 (commencing with Section 16780) of Chapter 4 of Part 3 of Division 2 of Title 2 of the Government Code. The approval of the voters for the issuance of bonds under this article includes approval for the issuance of bonds issued to refund bonds originally issued or any previously issued refunding bonds.