The court usher shall make a roll call of these witnesses. ART 310: The president shall order these witnesses to withdraw to the place set aside for them. They shall leave this place only to give their testimony. The president shall take, where the need arises, any measure necessary to prevent witnesses from discussing among themselves before testifying. ART 311: Should a summoned witness fail to appear, the court may, pursuant to a submission from the public prosecutor or even of his/her own motion, order that this witness should immediately be brought by law enforcement before it in order to be heard, or postpone the matter to the next hearing. In the latter case, all expenses for summons, documents for witness to travel and any other expenses intended to have this matter heard shall, excluding a legitimate excuse, be borne by the witnesses and he/she must be present, even forcefully, pursuant to a submission from the public prosecutor, through a ruling postponing the hearing to the next session. In any case, a witness who fails to appear in court or refuses to either take the oath or testify, may pursuant to a submission from the public prosecutor, be sentenced by the court pursuant to articles 84 and 85 of the Penal Code. Whoever is sentenced for failure to appear shall have the right to appeal. This appeal shall be filed no later than five days after the ruling has served in person or at the residence . The court shall rule on the appeal, either during the ongoing sitting or during a subsequent sitting. Section III - From the Investigation to Hearing ART 312- The president shall call on the accused person to attentively listen to the reading of the referral order. He/she shall order the court registrar to read this order loudly and clearly. ART 313: The president shall determine which of the accused persons will have to be heard first. A special hearing shall subsequently be organised with regards each of the other accused persons. ART 314: The president shall question the accused person and take down his/her statements. The president shall not voice his/her opinion concerning the guilt of the accused person. ART 315: Witnesses called by the various parties shall be heard during the proceeding, even if they did not give any statement during the investigation or if they were not summoned, on the condition that their names were not made known pursuant to the provisions of article 284. ART 316: During the hearing, the parties may object to a witness whose name was not made known to them or whom they were not properly informed about. The court shall rule on this objection. If this objection is considered grounded, these witnesses may be heard, for informative purposes, pursuant to the discretionary powers of the president ART 317: Only the direct ascendants and descendants of the parties, their brothers, their sisters, spouses, guardians or wards may be heard in any case. All other persons shall be admissible as witnesses, excluding those who cannot testify in court. Persons below the age of eighteen shall be unable to speak under oath. ART 318: However, testimonies given under oath by the persons referred to in the previous article shall not be null and void when neither the public prosecutor nor any of the parties objects to t he oath 52