{HEAD ~ A computer program} embodied in a tangible computer readable {TAIL ~ medium} for performing the method 20 
{ HEAD ~ A computer program } embodied in a tangible computer readable { TAIL ~ medium } for performing the method 20
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH