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