Texas Natural Resources Code - NAT RES § 162.037. Signatures and Seals

(a) The resolution authorizing the issuance of an installment or series of bonds may prescribe the extent to which facsimile signatures and facsimile seals may be used in lieu of manual signatures and manually impressed seals in executing the bonds and attached coupons.

(b) Interest coupons may be signed with the facsimile signatures of the chairman and secretary of the board.

(c) If an officer whose manual or facsimile signature appears on a bond or whose facsimile signature appears on a coupon ceases to be an officer before the bonds are delivered, the signature shall still be valid and sufficient for all purposes as if the officer had remained in office until the delivery of the bonds.