grassland Roger Federer of sina sports news Beijing time news on November 24, Stuttgart, Germany tournament organizing committee announced, Roger Federer has and they signed participation agreement in the next two years, this also means that has 34 year old Federer did not in 2017 retirement plan. Federer said, you always wanted to Stuttgart participating, but in previous years, the tournament has been after Wimbledon was. Now is the time to change to Wimbledon before the...