Pius, P. C. C. P. (1932). Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C..
Chicago-viite (17. p.)Pius, Pope; Catholic Church. Pope. Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C., 1932.
MLA-viite (8. p.)Pius, Pope; Catholic Church. Pope. Encyclical Letter of His Holiness, Pope Pius XI. Washington, D.C., 1932.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.