Eq. 8 indicates the values {HEAD ~ A} to {TAIL ~ Z} and AA to AE 
to
Eq . 8 indicates the values { HEAD ~ A } to { TAIL ~ Z } and AA to AE
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH