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