Treaties — Interpretation of — Whether right of an international organization to delegate its powers can be implied — Inclusio unius est exclusio alterius — European Coal and Steel Communlty Treaty, 1951.

International organization — Whether an international organization has right to delegate its powers — Whether such right to be implied — Distinction between delegation of discretion and delegation of execution — European Coal and Steel Community Treaty, 1951 — Period within which decision of High Authority can be annulled — Effect of challenge of that decision out of time — Right to challenge the validity of general decision when challenging validity of individual decision made in application of it — Duty to support decision by reasons.