3.__After issuance.__After issuance, all securities of the board must be conclusively presumed to be fully and duly authorized and issued under the laws of the State and any person or governmental unit is estopped from questioning their authorization, sale, issuance, execution or delivery by the board.

4.__Form of securities.__The securities of each issue must be dated, mature at such time or times not exceeding 40 years from their date or dates and bear interest at such rate or rates, including variable, floating or adjustable rates, as may be authorized by the board.__These securities may be made redeemable, callable or subject to purchase or tender before maturity, at such price or prices and under such terms and conditions as may be provided for by the board prior to the issuance of the securities. The board shall determine the form of the securities, including any interest coupons to be attached to the securities, if any, and the manner of execution of the securities and shall fix the denomination or denominations of the securities and the place or places of payment of principal and interest, which may be at any bank, national banking association or trust company within or without the State.__Securities must be executed in the name of the board by the manual or facsimile signature of such official or officials as may be authorized in the resolution to execute those securities.__Coupons, if any, attached to securities, must be executed with the facsimile signature of the official or officials designated in the resolution.__If any official whose signature or a facsimile of whose signature appears on any securities or coupons ceases to be an official before the delivery of the securities, the signature or the facsimile is valid and sufficient for all purposes, with the same effect as if the official had remained in office until the delivery.

Notwithstanding any of the other provisions of this Act or any recitals in any securities issued under this Act, all such securities are negotiable instruments issued under the laws of the State.__The securities may be issued in coupon or registered form, or both, as the board may determine.__Provisions may be made for the registration of any coupon securities as to principal alone and as to both principal and interest and for the reconversion into coupon securities of any securities registered as to both principal and interest.__The board may sell the securities in such manner, either at public or private sale, and