Charter - V : Powers of the tribunal and conduct of the trial - Art. 21.
Art. 21. The Tribunal shall not require proof of facts of common knowledge but shall take judicial notice thereof. It shall also take judicial notice of official governmental documents and reports of the United Nations, including the acts and documents of the committees set up in the various Allied countries for the investigation of war crimes, and the records and findings of military or other Tribunals of any of the United Nations.