A process token can optionally have multiple additional types of {HEAD ~ SIDs} based on {TAIL ~ other criteria}  
A process token can optionally have multiple additional types of { HEAD ~ SIDs } based on { TAIL ~ other criteria }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH