The authority to issue refunding bonds pursuant to this chapter is in addition to the authority granted by Chapter 3 of this part, and nothing in this chapter shall be deemed to amend or modify Chapter 3 of this part or be applicable to refunding bonds issued under the provisions thereof, except that the procedure specified in that chapter, insofar as it is adopted herein, is a part hereof, it being the intent of the Legislature to provide an alternative method of issuing refunding bonds.