APA (7th ed.) Citation

Pius XI. Papst. (1971). Encyclical letter "Quadragesimo Anno". Typis polyglottis Vaticanis.

Chicago Style (17th ed.) Citation

Pius XI. Papst. Encyclical Letter "Quadragesimo Anno". [Citta del Vaticano]: Typis polyglottis Vaticanis, 1971.

MLA (9th ed.) Citation

Pius XI. Papst. Encyclical Letter "Quadragesimo Anno". Typis polyglottis Vaticanis, 1971.

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