STANDARDS SECTION XVIII - TOURNAMENT STANDARDS OF PERFORMANCE the requirements of the ITF Rules of Tennis. The net band shall be cloth  or canvas (not plastic or vinyl), and the net shall extend to the ground. WTA/sponsor net post signage must be erected consistent with the  specifications provided by the WTA. There shall be no advertisement on  the strap, band, singles sticks, or net posts. Advertisement is permitted on the net as long as it is placed on the part  of the net that is within three (3) feet (0.914 meters) from the center of the  net posts and is produced in such a way that it does not interfere with the  vision of the players or the playing conditions (per the ITF Rules of Tennis). This advertising may not contain white or yellow. (See also Section XIII.B.4  - Net Post Signs.) b.  Advertising and Signage Restrictions 22. Officials and Officiating All WTA Tournaments are required to appoint, in consultation with the  WTA, an internationally certified Referee and Chief of Umpires to work in  conjunction with the Supervisor. All Chair Umpires appointed as designates for WTA Tournaments are  internationally certified Chair Umpires. All appointed officials are required to  be fully conversant with WTA Rules and procedures, the ITF Rules of Tennis,  and the Code for Officials, and together with the Supervisor, ensure they are  observed. All appointed officials must also be fluent in English.  At WTA/ATP joint events: (a) the selection of additional certified Chair Umpires  must be coordinated and approved by the Officiating Departments of both the  WTA and ATP; and (b) the Supervisors of the WTA and ATP will be responsible  for the daily assignments, using the designates from both the WTA and ATP  and the additional officials recruited by the Chief of Umpires.  The Referee shall: a. Referee i.  Be readily available to resolve any on-court dispute without delay,  supervise Medical Time Outs, and enforce the Code of Conduct. ii.  Decide, in consultation with the Supervisor, if a court is fit for play. iii. Assign and replace, when necessary, Chair Umpires, Line Umpires,  and Net Umpires. The assigning of these officials (but not their  326