Information exchange refusal limited to specified grounds; disputed tax claims do not justify refusal and domestic access limits apply. Article 7 permits refusal of information requests when requests are nonconforming, where domestic means have not been exhausted absent disproportionate difficulty, or where disclosure would contravene public policy. It exempts disclosure of trade or business secrets, confidential legal adviser-client communications produced for advice or proceedings, and measures that would violate the requested Party's laws or administrative practices, while preserving other specified obligations in the agreement.