Similarly, {HEAD ~ a memory access} refers to {TAIL ~ either a memory read} or a memory write operation 
refers to
Similarly , { HEAD ~ a memory access } refers to { TAIL ~ either a memory read } or a memory write operation
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH