{HEAD ~ The cutters} include {TAIL ~ at least two concentric arrays} of primary preform polycrystalline diamond cutters which are radially spaced so as to define an annular groove in the cutting profile, between the two arrays 
include
{ HEAD ~ The cutters } include { TAIL ~ at least two concentric arrays } of primary preform polycrystalline diamond cutters which are radially spaced so as to define an annular groove in the cutting profile , between the two arrays
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH