SOFIA - The head of Bulgaria's referees' commission should resign for "failing to get things under control", first division club Spartak Varna said on Sunday. "Referees' mistakes have cost us five or six points," Spartak's chief executive Zhivko Velikov said in a statement the day after relegation-threatened Spartak drew 1-1 at home against Vihren. The Varna-based club have criticised referees for "causing damage to the club" in several matches recently. "The referees' chief can't cope with his task and he should...let someone else get things under control," Velikov said. Bulgarian referees voted unanimously in September to appoint former international match official Dimo Momirov as the Bulgarian Football Union referees' commission chairman following the dismissal of the seven-member body several days earlier. The former commission headed by Borislav Alexandrov, who was suspended over match-fixing allegations, had been at loggerheads with match officials since the beginning of the season. The Balkan country's championship has been marred by accusations of bias among referees and a growing number of threats and violence levelled against referees.