APA (7th ed.) Citation

Catholic Church. Pope (1939-1958 : Pius XII) & Pius XII, P. (1951). Sempiternus rex: Encyclical letter of Pope Pius XII on the fifteenth centenary of the Council of Chalcedon. Issued September 8, 1951. National Catholic Welfare Conference.

Chicago Style (17th ed.) Citation

Catholic Church. Pope (1939-1958 : Pius XII) and Pope Pius XII. Sempiternus Rex: Encyclical Letter of Pope Pius XII on the Fifteenth Centenary of the Council of Chalcedon. Issued September 8, 1951. Washington: National Catholic Welfare Conference, 1951.

MLA (8th ed.) Citation

Catholic Church. Pope (1939-1958 : Pius XII) and Pope Pius XII. Sempiternus Rex: Encyclical Letter of Pope Pius XII on the Fifteenth Centenary of the Council of Chalcedon. Issued September 8, 1951. National Catholic Welfare Conference, 1951.