law: 86. Summoning witnesses.-
  (1) The convening officer, the presiding officer of a Security Guard Court, the Judge Attorney or, as the case may be, the Deputy Judge Attorney-General or the Additional Judge Attorney-General or the officer approved under section 80 or the Commander of the accused person may, by summons under his hand, require the attendance, at a time and place to be mentioned in the summons, of any person either to give evidence or to produce any document or other thing.
  (2) In the case of a witness who is subject to this Act, the summons shall be sent to his Commander and such officer shall serve it upon him accordingly.
  (3) In the case of any other witness, the summons shall be sent to the Magistrate within whose jurisdiction he may be, or resides, and such Magistrate shall give effect to the summons as if the witness was required in the Court of such a Magistrate.
  (4) When a witness is required to produce any particular document or other thing in his possession or power, the summons shall describe it with reasonable precision.