Catholic Church. Pope (1939-1958 : Pius XII), National Catholic Welfare Conference, & Pius XII, P. (1951). Sempiternus rex: Encyclical letter of Pope Pius XII on the fifteenth centenary of the Council of Chalcedo. National Catholic Welfare Conference.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Catholic Church. Pope (1939-1958 : Pius XII), National Catholic Welfare Conference, và Pope Pius XII. Sempiternus Rex: Encyclical Letter of Pope Pius XII on the Fifteenth Centenary of the Council of Chalcedo. Washington, D.C.: National Catholic Welfare Conference, 1951.
Trích dẫn kiểu MLA (xuất bản lần thứ 8)Catholic Church. Pope (1939-1958 : Pius XII), et al. Sempiternus Rex: Encyclical Letter of Pope Pius XII on the Fifteenth Centenary of the Council of Chalcedo. National Catholic Welfare Conference, 1951.