{HEAD ~ The bounding data values} for {TAIL ~ the set} of metrics characterize the bounding web site 
for
{ HEAD ~ The bounding data values } for { TAIL ~ the set } of metrics characterize the bounding web site
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH