In {HEAD ~ this case} {TAIL ~ algorithms} available from the following sources were used: Hirschberg, D. S 
In { HEAD ~ this case } { TAIL ~ algorithms } available from the following sources were used : Hirschberg , D. S
OTH HEAD HEAD HEAD HEAD HEAD HEAD TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH