The Board of Adjustment shall adopt rules and regulations in accordance with this Zoning Code and the Code of Iowa. The meetings of the Board of Adjustment shall be held at the call of the chairman and at such other times as the Board of Adjustment may determine. Such chairman, or in his absence the acting chairman, may administer oaths and compel the attendance of witnesses. All meetings of the Board of Adjustment shall be open to the public. The Board of Adjustment shall keep minutes of its proceedings, showing the vote of each member on each question, or if absent or failing to vote, indicating such fact, and shall keep records of its examinations and other official actions, all of which shall be immediately filed in the office of the Board of Adjustment and shall be a public record. The presence of three members shall be necessary to constitute a quorum.