Leo XIII, P. C. C. P. (19). Rerum Novarum- Encyclical Letter of Pope Leo XIII on The Condition of Labor. New York.
Chicago-referens (17:e uppl.)Leo XIII, Pope; Catholic Church. Pope. Rerum Novarum- Encyclical Letter of Pope Leo XIII on The Condition of Labor. New York, 19.
MLA-referens (8:e uppl.)Leo XIII, Pope; Catholic Church. Pope. Rerum Novarum- Encyclical Letter of Pope Leo XIII on The Condition of Labor. New York, 19.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.