Upon demand by the opposing parties, any party proposing to introduce exhibits into evidence in any proceeding before the Board shall furnish copies of exhibits requested to said opposing party. Upon proof of demand to furnish and failure to supply the said exhibit, it will be excluded from the hearing unless good and sufficient reason be shown by the party offering the same for the failure to furnish said exhibit to the party demanding the same.
285 Neb. Admin. Code, ch. 3, § 024.04