Section 6(3)(b) in Industrial Disputes (Central) Rules, 1957
(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.