APA (7th ed.) Citation

Pius XI, P. (1928). The Promotion of True Religious Unity; Encyclical Letter of His Holiness Pope Pius XI. Washington, D.C..

Chicago Style (17th ed.) Citation

Pius XI, Pope. The Promotion of True Religious Unity; Encyclical Letter of His Holiness Pope Pius XI. Washington, D.C., 1928.

MLA (8th ed.) Citation

Pius XI, Pope. The Promotion of True Religious Unity; Encyclical Letter of His Holiness Pope Pius XI. Washington, D.C., 1928.

Warning: These citations may not always be 100% accurate.