They are sure that a fault has been committed or there is an external interference ; and 1.2 .
It is very important that the REFEREES signal the end of a rally only if the following two conditions are fulfilled : 1.1 .
REFEREES are sure that a fault has been committed or there is an external interference ; and 1.2 .
It is very important that the REFEREES signal the end of a rally only if the following two conditions are fulfilled : 1.1 .