Gov. Code, § 53551

The legislative body of any local agency may issue negotiable coupon bonds, to be denominated refunding bonds, for the purpose of refunding any of the indebtedness of the local agency evidenced by bonds, whether due or not due, or which has or may hereafter become payable at the option of such local agency or by consent of the bondholders, or by any lawful means, whether such indebtedness, evidenced by bonds be now existing or may hereafter be created, and there shall not be moneys in a special fund in the treasury of such local agency irrevocably pledged to the payment or redemption of all such bonds; but the amount of such refunding bonds to be issued under the provisions of this article shall first be determined by such legislative body by resolution entered upon the minutes of such legislative body.