TITLE IV CHAPTER I MISCELLANEOUS PROVISIONS Article 98 The President shall instruct any person who is required to take an oath before the Court, as witness or expert, to tell the truth or to carry out his task conscientiously and impartially, as the case may be, and shall warn him of the criminal liability provided for in his national law in the event of any breach of this duty. Article 99 Subject to the provisions of the protocol and after consultation, the Court shall adopt supplementary rules concerning its practice in relation to: (a) Letters rogatory; (b) Reports of perjury by witnesses or experts. Article 100 The Court may issue practice directions relating in particulars to the preparation and conduct of the hearings before it and to the lodging of written statements of case or written observations. Article 101 These Rules, which are authentic in the languages mentioned in Article 87 of the Treaty shall be published in the official journal of Community and shall become valid soon after their publication.