{TAIL ~ A process} for producing polyethylene comprises polymerizing ethylene or copolymerizing ethylene with other α olefin in the presence of {HEAD ~ a catalyst system} obtained by bringing the following components to in contact with one another: 
{ TAIL ~ A process } for producing polyethylene comprises polymerizing ethylene or copolymerizing ethylene with other α olefin in the presence of { HEAD ~ a catalyst system } obtained by bringing the following components to in contact with one another :
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