Extract from Powers and Duties of the Referee, within Law 5
• takes disciplinary action against players guilty of cautionable
and sending-off offences. He is not obliged to take this action immediately
but must do so when the ball next goes out of play
Extract from the Guidelines for Referees with reference to Law 5
If the offence warrants a caution, it must be issued at the next stoppage.
However, unless there is a clear advantage, it is recommended that the referee
stops play and cautions the player immediately. If the caution is NOT issued at
the next stoppage, it cannot be shown later.