Once the album has been created, {HEAD ~ the system} validates {TAIL ~ the album} to determine if the user has created any modeling errors 
validates
Once the album has been created , { HEAD ~ the system } validates { TAIL ~ the album } to determine if the user has created any modeling errors
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH