A Board, Court, Labour Court or Tribunal or an Arbi- trator may accept, admit or call for evidence at any stage of the proceedings before it/him and in such manner as it/he may think fit.
20. Administration of Oath:
Any member of a Board or Court or Presiding Officer of a Labour Court, Tribunal or an Arbitrator may administer an oath.
21 Summons:
A Summons issued by a Board, Court, Labour Court or Tribunal shall be in Form "D" and may require any person to produce before it any books, papers or other documents and things in the possession of or under the control of such person in any way relating to the matter under investigation or adjudication by the Board, Court, Labour Court or Tribunal which the Board, Court, Labour Court or Tribunal thinks necessary for the purposes of such investigation or adjudication.
22. Service of Summons or Notice:
Subject to the provisions contained in rule 24, any notice, summons, process or order issued by a Board, Court. Labour Court, Tribunal or an Arbitrator empowered to issue such notice, summons, or order, may be served either personally or by registered post.
23. Description of parties in certain cases:
Where in any proceeding before a Board, Court. Labour Court. Tribunal or an Arbitrator, there are numerous per- sons arrayed on any side, such persons shall be described as follows:-
(1) all such persons as are members of any trade union or association shall be described by the name of such trade union or association; and
(2) all such persons as are not member of any trade union or association shall be described in such manner as the Board, Court, Labour Court. Tribunal or Arbitrator, as the case may be, may determine.