Case C-221/11: Judgment of the Court (Grand Chamber) of 24 September 2013 (request for a preliminary ruling from the Oberverwaltungsgericht Berlin-Brandenburg — Germany) — Leyla Ecem Demirkan v Bundesrepublik Deutschland (EEC-Turkey Association Agreement — Additional Protocol — Article 41(1) — ‘Standstill’ clause — Visa requirement for admission to the territory of a Member State — Freedom to provide services — The right of a Turkish national to enter a Member State in order to visit a family member and, potentially, to receive services)