Council may hold special meetings at the place selected for their regular meetings commencing at such hour as they determine. The special meetings shall be called by the City Clerk upon the written request of the Mayor or of three members of Council. At least two days' written notice of the time, place and purposes of the special meetings shall be given to each member of Council and the Mayor by mail or manual delivery to the person or the person's residence, and the meeting may not consider or act upon any subject not specifically mentioned in such notice.