Cal. Mil. & Vet. Code § 460

Each miliary court shall have the power of a superior court of this State to compel by subpena, subpena duces tecum, and attachment, the attendance of witnesses, both civilian and military, and the production of books, papers, and documents, and to punish for contempt a witness duly subpenaed for nonattendance or for refusal to be sworn or testify or to produce books, papers, and documents. Military courts may also take by commission the testimony of witnesses who can not reasonably be produced at the trial in the same manner as a superior court.