Streets and Highways Code § 25406

All revenue bonds shall be signed by the treasurer of the district, attested by the secretary of the board of directors thereof and shall have the official seal of the district attached thereto. The form of the interest coupons attached to the bonds shall be determined by the treasurer subject to the approval of the board of directors. The signature on the interest coupons shall be that of the treasurer and may be either written or engraved or printed facsimile.