A detailed record of each meeting shall be made and kept which shall contain copies of all written, printed, or graphic materials presented. The Secretary shall have prepared minutes of each meeting which shall state the time and place it was held and attendance by Commission members and staff and which shall contain a complete summary of matters discussed and conclusions reached and an explanation of the extent of public participation, including names of persons who presented oral or written statements; and he shall send a copy to all members of the Commission for their approval. Subsequent to such approval, the minutes shall be certified by the Secretary. The minutes and any completed reports, studies, agenda or other documents made available to, or prepared for or by, the Commission shall be available for public inspection and, at the requesting party's expense, for copying at the offices of the Commission.