The association shall determine the form of the bonds, including any interest coupons to be attached thereto, and shall fix the denomination or denominations of the bonds and the place or places of payment of the principal and interest thereon, which may be at any bank or trust company within or without the state. The bonds may be issued in coupon or registered form, or both, as the association may determine, and provision may be made for the registration of any coupon bond as to principal alone or as to both principal and interest.