State responsibility — Claims — State control over private claims-Express waiver of claims in treaty — Waiver covering claims of “nationals” — Relevant dates at which such nationality must be possessed for claims to be covered by waiver — Claims arising out of war — Dates of termination of hostilities and ratification of treaty analogous to treaty of peace — Austrian State Treaty, 1955, Article 23 — Treaty for Settlement of Proprietary Relations between the Federal Republic of Germany and Austria.