detect an input corresponding to a users selection of one of {HEAD ~ the plurality} of {TAIL ~ entries}; and 
detect an input corresponding to a users selection of one of { HEAD ~ the plurality } of { TAIL ~ entries } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH