Article 19
On the inquiry both sides must be heard.
At the dates fixed, each party communicates to the commission and to the other party the statements of facts, if any, and, in all cases, the instruments, papers, and documents which it considers useful for ascertaining the truth, as well as the list of witnesses and experts whose evidence it wishes to be heard.
Article 20
The commission is entitled, with the assent of the parties, to move temporarily to any place where is considers it may be useful to have recourse to this means of inquiry or to send one or more of its members. Permission must be obtained from the state on whose territory it is proposed to hold the inquiry.
Article 21
Every investigation, and every examination of a locality, must be made in the presence of the agents and counsel of the parties or after they have been duly summoned.
Article 22
The commission is entitled to ask either party for such explanations and information as it considers necessary.
Article 23
The parties undertake to supply the commission of inquiry, as fully as they may think possible, with all means and facilities necessary to enable it to become completely acquainted with, and to accurately understand, the facts in question.
They undertake to make use of the means at their disposal, under their municipal law, to insure the appearance of the witnesses or experts who are in their territory and have been summoned before the commission.
If the witnesses or experts are unable to appear before the commission, the parties will arrange for their evidence to be taken before the qualified officials of their own country.
Article 24
For all notices to be served by the commission in the territory of a third Contracting Power, the commission shall apply direct to the Government of the said power. The same rule applies in the case of steps being taken on the spot to procure evidence.
The requests for this purpose are to be executed so far as the means at the disposal of the power applied to under its municipal law allow. They cannot be rejected unless the power in question considers they are calculated to impair its sovereign rights or its safety.
