Ind. Code § 6-6-1.1-907
(b) No refund shall be made under this section unless the written claim describes the reason the refund should be allowed. The claim must be sworn to by the claimant and filed with the administrator, on forms prescribed by the administrator, within three (3) years after the end of the calendar year containing the taxable period in which the tax was erroneously collected.
As added by Acts 1979, P.L.79, SEC.1. Amended by Acts 1980, P.L.51, SEC.44; P.L.97-1987, SEC.11.