APA (7th ed.) Citation

Catholic Church. Pope (1958-1963 : John XXIII) & John XXIII, P. (1963). Pacem in terris: Encyclical letter of Pope John XXIII, April 11, 1963. National Catholic Welfare Conference.

Chicago Style (17th ed.) Citation

Catholic Church. Pope (1958-1963 : John XXIII) and Pope John XXIII. Pacem in Terris: Encyclical Letter of Pope John XXIII, April 11, 1963. Washington: National Catholic Welfare Conference, 1963.

MLA (8th ed.) Citation

Catholic Church. Pope (1958-1963 : John XXIII) and Pope John XXIII. Pacem in Terris: Encyclical Letter of Pope John XXIII, April 11, 1963. National Catholic Welfare Conference, 1963.