Appeal against advance ruling to Appellate Authority requires timely filing within prescribed period, with possible extension for sufficient cause. An appeal lies to the Appellate Authority against advance rulings under section 98 by the concerned officer, the jurisdictional officer or the applicant. Appeals must be filed within a prescribed period from communication of the ruling; the Appellate Authority may, on sufficient cause, allow a further limited extension. Appeals are subject to prescribed formalities as to form, fee and verification.