Form; execution; delivery.

The refunding bonds herein provided for may be issued in registered form, or may be coupon bonds with the privilege of registration either as to principal only or as to both principal and interest, and shall be executed in the manner and by the officials provided in the resolution authorizing same. Except one signature on each bond, the signatures on the bonds and coupons may be facsimile signatures. Bonds and coupons duly executed by officials then in office may be negotiated and delivered after such officials have ceased to hold such office. The authentication or certificate of a registrar may be required on the bonds.