Assistance in collection of taxes: cross-border revenue claims may be collected or conserved by other Contracting State under domestic law. Article 28 permits mutual assistance in collecting revenue claims: the requested Contracting State may enforce or take conservatory measures on behalf of the requesting State, applying its own laws and procedures as if the claim were its own, while such assistance does not confer priority or altered time limits and disputes over existence, validity or amount remain within the requesting State's courts or administrative bodies.