Assistance in tax collection: treaty allows mutual enforcement and conservancy measures subject to domestic law limits and exceptions. Contracting States shall mutually assist in collecting revenue claims-including taxes, interest, penalties and collection costs-by accepting such claims for collection or conservancy at the request of the competent authority and enforcing them under the assisting State's domestic laws as if they were its own. Assistance does not change applicable time limits or priorities, does not confer jurisdiction in the assisting State to litigate the claim's existence or amount, and may be suspended if the claim ceases to meet conditions. Assistance is subject to exceptions for conflicts with domestic law or administrative practice, public policy, failure to pursue reasonable measures, or disproportionate administrative burden.