By Mark Gleeson JOHANNESBURG (Reuters) – The International Tennis Federation (ITF) is confident its anti-doping programs are working effectively and labeled recent criticisms of the system by Roger Federer and Novak Djokovic unfair. “I think that tennis is doing a good job in the programs it has and we’ve had two fairly high-profile cases recently with Marin Cilic and Viktor Troicki and let’s not forget both of those cases resulted in violations for the athletes concerned,” the ITF’s anti-doping manager Stuart Miller said on Thursday.