Geneva: World football’s governing body is exploring controversial changes to the game including a new refereeing system and possible changes to points scoring, FIFA president Sepp Blatter said yesterday. A refereeing system involving four linesmen will be tested during either European or World youth tournaments this summer, FIFA confirmed. “It’s a first agreement with Michel Platini. We said that we need to help the referee, he must be given more assistants,” Blatter said.