The city may issue its revenue bond anticipation notes which shall be payable by exchange for, or out of the proceeds of the sale of, a designated series of revenue bonds referred to in the bond anticipation notes. The reference to the revenue bonds shall specify a maximum rate of interest to be borne by said bonds and may provide that said bonds shall be offered for sale but if no proposals shall be received, the sole remedy of the holders of the revenue bond anticipation notes shall be either to accept the bonds at the specified maximum interest rate, or to extend the maturity of the revenue bond anticipation notes for one or more specified additional periods of not less than six months each during which additional offers of the bonds may be made.