For any bonds issued in connection with Section 19, 20 or 21 [5-11-19, 5-11-20 or 5- 11-21 NMSA 1978] of the Public Improvement District Act, the district board shall prescribe the denominations of the bonds, the principal amount of each issue and the form of the bonds and shall establish the maturities, which shall not exceed thirty years, interest payment dates and interest rates, whether fixed or variable, not exceeding the maximum rate stated in the notice of the election or the resolution of the district board. The bonds may be sold by competitive bid or negotiated sale for public or private offering at, below or above par. The proceeds of the bonds shall be deposited with the treasurer, or with a trustee or agent designated by the district board, to the credit of the district to be withdrawn for the purposes provided by the Public Improvement District Act. Pending that use, the proceeds may be invested as determined by the district. The bonds shall be made payable as to both principal and interest solely from revenues of the district, and shall specify the revenues pledged for such purposes, and shall contain such other terms, conditions, covenants and agreements as the district board deems proper. The bonds may be payable from any combination of taxes, levies or revenues of the types described in Sections 19, 20 and 21 of the Public Improvement District Act.