Section 6(3) in M.P. Industrial Disputes Rules, 1957
(3)The notice to the workmen shall be sent-(a)in the case of workmen who are members of a trade union, to the President or Secretary of the trade union; and(b)in the case of workmen who are not members of a trade union, to any one of the five representatives of the workmen who have attested the application made under Rule 3; and in this case a copy of the notice shall also be sent to the employer who shall display copies thereof on notice boards in a conspicuous manner at the main entrance to the premises of the establishment.
