Human rights — Right to strike in public service — Treaty of Versailles, 1919, Part XIII — International Labour Organization Convention Concerning Freedom of Association and Protection of the Right to Organize, 1948 — Universal Declaration of Human Rights, 1948 — International Covenant on Economic, Social and Cultural Rights, 1966 — Alberta statute prohibiting strikes by employees in public service — Whether contrary to Canada’s international legal obligations — Public Service Employee Relations Act 1977

Sources of international law — Customary international law — Treaties — Custom as evidence of general practice — International conventions establishing rules expressly recognized by contesting States — Right to strike ensured to all employees including public employees except in essential services — Whether part of customary international law — Whether conventional international law — Treaty of Versailles, 1919, Part XIII — International Labour Organization Convention concerning Freedom of Association and Protection of the Right to Organize, 1948 — Universal Declaration of Human Rights, 1948 — United Nations Covenant on Economic, Social and Cultural Rights, 1966 — The law of Canada