Special meetings may be called at any time, as follows:

1. (a) A special meeting of a three-member board of library trustees may be called by two trustees, by written notices served upon each member at least 12 hours before the time specified for the meeting.
2. (b) A special meeting of a five-member board of library trustees may be called by three trustees, by written notices served upon each member at least 12 hours before the time specified for the meeting.