to summon witnesses to the Trial and to require their attendance and testimony and to put questions to them,
(b)
to interrogate any Defendant,
(c)
to require the production of documents and other evidentiary material,
(d)
to administer oaths to witnesses,
(e)
to appoint officers for the carrying out of any task designated by the Tribunal including the power to have evidence taken on commission.
Article 18. The Tribunal shall