Case C-553/15: Judgment of the Court (Fourth Chamber) of 8 December 2016 (request for a preliminary ruling from the Consiglio di Stato — Italy) — Undis Servizi Srl v Comune di Sulmona (Reference for a preliminary ruling — Public service contracts — Award of the contract without initiating a tendering procedure — So-called ‘in-house’ award — Conditions — Similar control — Performance of the essential activity — Successful public capital tendering company owned by several local authorities — Activity also carried out for the benefit of local authorities which are not shareholders — Activity imposed by a public authority which is not a shareholder)