Pius, P. C. C. P. (1926). The kingdom of Christ. [The letter of Pope Pius XI. instituting the new feast of the kingdom of Christ. New York.
Chicago Style (17th ed.) CitationPius, Pope; Catholic Church. Pope. The Kingdom of Christ. [The Letter of Pope Pius XI. Instituting the New Feast of the Kingdom of Christ. New York, 1926.
MLA (8th ed.) CitationPius, Pope; Catholic Church. Pope. The Kingdom of Christ. [The Letter of Pope Pius XI. Instituting the New Feast of the Kingdom of Christ. New York, 1926.
Warning: These citations may not always be 100% accurate.