Constituting the Eighteenth Supplemental Ordinance to the General Gas Works Revenue Bond Ordinance of 1975 (the "1975 General Ordinance"); authorizing the Mayor, the City Controller and the City Solicitor, or a majority of them, to sell, either at public or private sale, Gas Works Revenue Bonds, Eighteenth Series (1975 General Ordinance), of the City of Philadelphia, in one or more subseries (the "Eighteenth Series Bonds") to be issued to pay the cost of refunding or redeeming all or a portion of certain outstanding Gas Works Revenue Bonds and other Project Costs, as hereinafter more particula — Open Common Ground