Further anti-discrimination principles were established by such human rights instruments as the International Covenant on Civil and Political Rights and the International Covenant on Economic, Social and Cultural Rights, which came into force in 1966. Together they form the most comprehensive international code of legally binding provisions in the area of human rights. The two Covenants develop and supplement the provisions of the Universal Declaration, and the three instruments together make up what has come to be known as the International Bill of Human Rights.