Article 115 of the Interpretation of the Supreme People's Court on the Application of the Civil Procedure Law of the People's Republic of China stipulates that the certification materials submitted by the unit to the people's court shall be signed or sealed by the person in charge of the unit and the person who made the certification materials, and stamped with the seal of the unit. The people's court may investigate and verify the certification materials issued by the unit and the personnel who made the certification materials. When necessary, the person who made the certification materials may be required to testify in court.

if the unit and the personnel who make the certification materials refuse to be investigated and verified by the people's court, or the personnel who make the certification materials refuse to testify in court without justifiable reasons, the certification materials shall not be used as the basis for determining the facts of the case.