Another advantage is that tracking records do not have to be explicitly created in {TAIL ~ a tracking operation} for marked items contained in {HEAD ~ another marked item} 
Another advantage is that tracking records do not have to be explicitly created in { TAIL ~ a tracking operation } for marked items contained in { HEAD ~ another marked item }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD