{HEAD ~ Exemplary} of {TAIL ~ such a system} is a MgCl2 supported TiCl3  
{ HEAD ~ Exemplary } of { TAIL ~ such a system } is a MgCl2 supported TiCl3
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH