Process 2000 begins with {TAIL ~ operation} 2002, where the reader retrieves at least a TPK and an ES from {HEAD ~ a tag} 
Process 2000 begins with { TAIL ~ operation } 2002 , where the reader retrieves at least a TPK and an ES from { HEAD ~ a tag }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD