In addition to {HEAD ~ the master calendar}, a user may add {TAIL ~ secondary calendars} in the present invention 
In addition to { HEAD ~ the master calendar } , a user may add { TAIL ~ secondary calendars } in the present invention
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH