Section 89(2)(a) in The Central Goods and Services Tax Rules, 2017
(a)the reference number of the order and a copy of the order passed by the proper officer or an appellate authority or Appellate Tribunal or court resulting in such refund or reference number of the payment of the amount specified in sub-section (6) of section 107 and sub-section (8) of section 112 claimed as refund;