1. When it is deemed necessary, the Review Board may request the reference agency to present the administrative documents concerned with the disclosure decision, etc.. In this case, no one may request to the Review Board the disclosure of those administrative documents presented to the Review Board. 2. The reference agency shall not turn down a request made in accordance with the preceding paragraph. 3. When it is deemed necessary, the Review Board may request to the reference agency that it produce and submit to the Review Board materials classifying or arranging in a manner specified by the Review Board the contents of the information recorded in the administrative documents concerned with the disclosure decision, etc. 4. In addition to the provisions of the first paragraph and the preceding paragraph of this Article, the Review Board may, in relation to the matter concerned with an appeal, request the appellant, intervenor, or the reference agency (hereinafter referred to as "appellant, etc.") to submit written opinions or other materials, and may have persons deemed appropriate make statements about facts of which they have knowledge or request expert opinions or make any other necessary investigations. Article 28 Statements of Opinion 1. When there is a petition from an appellant, etc., the Review Board shall provide an opportunity for that appellant, etc. to orally deliver his or her opinion. However, this shall not apply when the Review Board deems that it is not necessary. 2. As regards the text of the preceding paragraph, upon receiving the Review Board's permission, an appellant or an intervenor may appear together with assistants. Article 29 Submission of Written Opinions, Etc. Appellants, etc. may submit written opinions or other materials to the Review Board. However, when the Review Board fixes a suitable period of time within which written opinions or other materials should be submitted, the submission shall take place within that time period. Article 30 Procedure for Investigations by Board Members When it is deemed necessary the Review Board may have a designated member inspect the administrative documents that were submitted in accordance with Article 27, paragraph 1, investigate in accordance the same Article, paragraph 4, or hear statements of opinion by the appellant, etc. in accordance with the text of Article 28, paragraph 1. Article 31 Inspection of Submitted Materials 1. The appellant, etc. may request to the Review Board to inspect written opinions or materials that were submitted to the Review Board. In this case, if it is not deemed that there is a risk that a third party's interests will be harmed, or if there is not another justifiable reason, the Review Board shall not refuse inspection. 2. The Review Board may fix the time, date and place for inspection as provided for in the preceding paragraph.