Treaties — Interpretation — Application — Agreement between Government of Australia and Government of Republic of India for Avoidance of Double Taxation and Prevention of Fiscal Evasion with Respect to Taxes on Income, 1991 — Operation of “business profits rule” — Article 7 — Operation of “royalties provision” — Article 12 — Principles of interpretation — Vienna Convention on the Law of Treaties, 1969, Article 31 — Whether source State having right to tax royalties under Article 7 or 12 — The law of Australia