SEC. 5. REFUNDING OUTSTANDING BONDS.

   The city shall have the right to refund any outstanding bonds by the issuance of new bonds in lieu thereof, at the same, higher or a lower rate of interest, and may apply thereto the sinking fund belonging to any series of bonds so refunded, and may pay and retire any bond by using the sinking fund thereof. The city shall have the same right to refund any bonds assumed as a result of annexations.

SEC. 6. BONDS PREVIOUSLY AUTHORIZED.

   All unissued bonds previously authorized by any election or by any provisions in a former city charter may be issued and are hereby validated.

SEC. 7. BONDS INCONTESTABLE.

   All bonds of the city having been approved by the attorney general and registered by the comptroller of the public accounts shall be incontestable, except for forgery, fraud or exceeding the limit fixed by the Charter.

SEC. 8. EXECUTION OF BONDS.

   All bonds must be signed by the mayor and countersigned by the city manager or the city manager’s designee and must have the seal of the city impressed on each bond; provided, that the bond ordinance or ordinances may provide for the bonds and any attached interest coupon to be signed by facsimile signatures and for the seal of the city on the bonds to be a facsimile as provided by the laws of the State of Texas. Such bonds shall mature serially or otherwise not to exceed 40 years from their date. (Amend. of 4-2-83, Prop. No. 6; Amend. of 5-1-93, Prop. No. 7)

SEC. 9. SINKING FUND FOR GENERAL OBLIGATION BONDS.

   It shall be the duty of the city council each year to levy a tax sufficient to pay the interest and provide the necessary sinking fund required by law on all general obligation bonds outstanding, and if a deficiency appears at any time in such fund the council shall, for the next succeeding year, levy an additional tax sufficient to discharge such deficiency.