24The Court further pointed out, at paragraph 15 of the ARO Lease judgment, that the place where the supplier has established his business is a primary point of reference inasmuch as there is no purpose in referring to another establishment from which the services are supplied unless reference to the main place of business does not lead to a rational result for tax purposes or creates a conflict with another Member State. Consequently, as the Court held at paragraph 16 of the same judgment, for a supply of services, reference to an establishment other than the main place of business is possible only if that establishment possesses a sufficient degree of permanence and a structure adequate, in terms of human and technical resources, to supply the services in question on an independent basis.