In order to designate any area or property as either a Landmark or a Historic District, the Commission and the City Council shall make express findings that the area or property in question meets one or more of the criteria of Section 58-61 of the Municipal Code and has integrity of design.  Any person, group of persons, corporation or association, including but not limited to the Commission may apply to the Belvidere Historic Preservation Commission for the designation of a Landmark or Historic District. Application for shall be filed with the planning department and reviewed by the Commission and by the City Council. Applications for designation of Historic Districts shall contain the names of no less than 51 percent of the property owners as signatories to the application.