C-527/16Salzburger Gebietskrankenkasse and Bundesminister für Arbeit, Soziales und Konsumentenschutz v Alpenrind GmbH and Others

Domstolens egne nøkkelord

Reference for a preliminary ruling — Social security — Regulation (EC) No 987/2009 — Articles 5 and 19(2) — Workers posted in a Member State other than that in which the employer usually carries out its activities — Issue of the A1 attestations by the Member State of origin after recognition by the host Member State that the workers are subject to its social security scheme — Opinion of the Administrative Board — Incorrect issue of A1 certificates — Finding — Binding nature and retroactive effect of those certificates — Regulation (EC) No 883/2004 — Legislation applicable — Article 12(1) — Concept of a person ‘sent to replace another person’.

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