Section 18(3)(b) in The Industrial Disputes Act, 1947
(b)all other parties summoned to appear in the proceedings as parties to the dispute, unless the Board, [arbitrator,] [ Inserted by Act 36 of 1964, Section 9 (w.e.f. 19.12.1964).] [Labour Court, Tribunal or National Tribunal] [ Substituted by Act 36 of 1956, Section 13, for " or Tribunal" (w.e.f. 10.3.1957).], as the case may be, records the opinion that they were so summoned without proper cause;