State responsibility — Nature and kinds of — For debts — Claim for unjust enrichment related to a dishonoured cheque — Whether cheque drawn by State — owned bank — Iran- United States Claims Settlement Declaration, 1981, Article VII(3) — The law and practice of the Iran- United States Claims Tribunal

State responsibility — Claims — Nationality of — Claim for unjust enrichment — Continuity of nationality of ownership of claim — Iran-United States Claims Settlement Declaration, 1981 — The law and practice of the Iran- United States Claims Tribunal

Disputes — Arbitration — In general — The law applied by arbitral tribunals — Iran- United States Claims Settlement Declaration, 1981 — Claim for unjust enrichment — Applicable law — Whether national law — Article V — General principles of law — The law and practice of the Iran- United States Claims Tribunal

Disputes — Arbitration — Procedure — Competence — Iran-United States Claims Settlement Declaration, 1981 — Claim for unjust enrichment related to a dishonoured cheque — Jurisdiction — Whether cheque drawn by State-owned bank — Article VII (3) — Continuity of nationality of ownership of claim — Unjust enrichment as an element of State responsibility — Law applicable to claim — Article V — General principles of law — Evidence of unjust enrichment — The law and practice of the Iran-United States Claims Tribunal