State immunity — Jurisdictional immunity — Employment dispute — Employee of foreign embassy — Claim for damages for non-payment of social security contributions — Whether foreign State entitled to invoke jurisdictional immunity — Whether jurisdiction of national courts dependent upon declaration of submission by foreign State — Whether restrictive theory of immunity to be applied in accordance with customary international law and practice

State succession — Contract — Employment claim — Embassy employee of former Soviet Union — Whether Russian Federation liable for obligations of former Soviet Union — The law of Argentina