Special meetings may be called by the Mayor, the City Clerk or any three Councilpersons. The City Clerk shall prepare a notice of the special meeting stating time, place and object, and this notice shall be served personally upon each member of Council, or left at their usual place of residence at least 48 hours before the time of the meeting. It shall also be the duty of the City Clerk, immediately upon receipt of written request, to make diligent effort to notify each member of Council in person, either by telephone or otherwise, of such special session. The City Clerk shall further post on the bulletin board on the first floor in City Hall at least 48 hours before such meeting notice to the public of the time, place and purpose of the meeting and in addition shall notify the news media, including each local newspaper, radio station and television station, of the time, place and purpose of the meeting by written notice at least 48 hours in advance of any special meeting. However, the foregoing notice shall not be required in the event of an emergency requiring immediate official action.