Meetings. Meetings of the Board shall be held at the call of the Chairman and at such other times as the Board, in its rules of procedure, may specify. The Chairman, or in his absence the Acting Chairman or hearing officer appointed from the membership of the Board presiding, shall have the power to administer oaths and issue subpoenas to compel the attendance of witnesses and the production of relevant documents and papers, including witnesses and documents requested by the parties. The Board or hearing officer, as the case may be, shall keep minutes of its proceedings showing the vote of each member upon each question, or if absent or failing to vote, indicating such fact and shall keep records of its examinations and other official actions. The records of the Board shall be kept in the office of the Zoning Officer and shall be a public record. The Board shall meet at least once a month if it has any cases to come before it.