Assistance in the collection of taxes: cross-border enforcement and conservancy by contracting states upon request. Contracting States shall mutually assist in collecting tax-related revenue claims-including interest, penalties and collection costs-at the request of a competent authority. If a claim is enforceable and the debtor cannot prevent collection, the requested State will collect it under its domestic tax enforcement rules. If the requesting State may take conservancy measures, the requested State will apply analogous conservancy measures. Accepted claims receive no special time-limit or priority treatment in the requested State. Disputes on existence, validity or amount remain within the courts or administrative bodies of the requesting State. Assistance is limited by domestic law, public policy, prior reasonable collection efforts, and proportionality of administrative burden.