{HEAD ~ The coring unit} may include {TAIL ~ a frame} within which a coring bit is contained 
include
{ HEAD ~ The coring unit } may include { TAIL ~ a frame } within which a coring bit is contained
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH