Disputes — International Court of Justice — Contentious jurisdiction — Procedure — Application for permission to intervene — Statute of the International Court of Justice, 1945, Article 62 — Requirement that intervener show an interest of a legal nature which might be affected by decision — Scope of — Object of intervention — Court asked to take account of intervener's claims to sovereign rights — Whether Court thereby called upon to recognize rights — Nature of intervention — Introduction of a fresh dispute — Principle of consent underlying jurisdiction of the Court — Whether jurisdictional link between intervening State and original parties required — Whether Article 62 itself providing basis of jurisdiction — Protection of legal interests of third States — Statute of the International Court of Justice, 1945, Article 59 — Procedural economy of means — Treaties — Interpretation of — Miscellaneous — Respective spheres of application — Consideration of preparatory work