Charter - V : Powers of the tribunal and conduct of the trial - Art. 23.
Art. 23. One or more of the Chief Prosecutors may take part in the prosecution at each Trial. The function of any Chief Prosecutor may be discharged by him personally, or by any person or persons authorized by him.
The function of Council for a Defendant may be discharged at the Defendant's request by any Counsel professionally qualified to conduct cases before the Courts of his own country, or by any other person who may be specially authorized thereto by the Tribunal.