The initiative and referendum powers, reserved to the people under the Ohio Constitution, shall be exercised in the manner provided by the Ohio Constitution, the laws of the State of Ohio and this Charter, except: that any initiative or referendum petition filed with the Auditor of the City of Oxford shall contain the signatures of not less than ten percent of the voters who voted at the preceding election for the office of Governor; that when a petition having the required number of signatures is filed with the City Auditor, it shall be held in the Auditor's office for a period of 15 days before certification of the text of the proposed ordinance is made to the Board of Elections; that the committee designated by the petitioners to file said petition shall consist of five members. In all other respects, the procedure with reference to initiative and referendum petitions shall be the same as that provided by the Constitution, laws of the State of Ohio and this Charter. Whenever the Council is required to pass more than one ordinance to complete the legislation necessary to complete and pay for any public improvement, the referendum shall apply only to the first ordinance to be passed and not to any subsequent ordinance in the series relating thereto. Resolutions are not subject to referendum.