EFTA Court - Advisory Opinion of the Court of 14 June 2001 in Case E-4/00 (Request for an Advisory Opinion from the Administrative Court for the Principality of Liechtenstein): Dr Johann Brändle (Right of establishment — Single practice rule — Justification by overriding reasons of general interest) (Pursuant to Article 27(5) of the Rules of Procedure only the English and German texts are authentic)