Treaties — Interpretation of — Principles and rules of — Natural meaning of words — Statement of facts not constituting legal obligation — Restrictive interpretation — Exclusion by “broad language” of treaty.

Treaties — Interpretation of — Consideration of preparatory work — Restraint in use of.

Disputes — Arbitration — The award — Scope of — Rationes decidendi not part of award — Exchange of letters after award to resolve ambiguity.

International organization — Officials — Immunity from national income tax.