53 Pa. C.S. § 8146
Bonds or notes, including tax anticipation notes, shall be signed by such officers of the local government unit, and coupon bonds shall have attached thereto interest coupons bearing the facsimile signature of such officer of the local government unit, and the bonds or notes may be sealed with the seal of the local government unit or a facsimile thereof, all as may be determined by the governing body. Bonds or notes may provide that they are not valid or enforceable unless authenticated by a specified bank, bank and trust company or trust company. If any one signature on a bond or note, including the signature of the authenticating party, is manual, all other signatures may be by facsimile. If any officer whose signature, or a facsimile of whose signature, appears on any notes, bonds or coupons ceases to be such officer before the delivery of the notes or bonds, the signature or the facsimile shall nevertheless be valid and sufficient for all purposes as if he had remained in office until delivery. Any note, bond or coupon may bear the facsimile signature of, or may be signed by, those persons as at the actual time of the execution of the note, bond or coupon were the proper officers to sign although at the date of the instrument these persons may not be such officers.
53 Pa.C.S. § 8146