Del. Code tit. 30, § 330

The Tax Appeal Board, for the purpose of its hearings, may issue subpoenas, compel the attendance of witnesses, administer oaths, take testimony and compel the production of pertinent books, payrolls, accounts, papers, records and documents, and in case any person summoned to testify or to produce any relevant or material evidence refuses to do so without reasonable cause, the Tax Appeal Board may certify the fact of any such refusal to the Superior Court of the county in which such hearing is held and such Superior Court may proceed against the person so refusing for contempt and may punish such person, if found guilty, in such manner as persons are punished for contempt of court.