APA
John Paul II, . (1987). Encyclical Letter Sollicitudo rei Socialis of the Supreme Pontiff John Paul II for the twentieth Anniversary of Populorum Progressio. Vatican: Libreria Editrice Vaticana.
Chicago
John Paul II, . 1987. Encyclical Letter Sollicitudo rei Socialis of the Supreme Pontiff John Paul II for the twentieth Anniversary of Populorum Progressio. Vatican: Libreria Editrice Vaticana.
Harvard
John Paul II, . (1987). Encyclical Letter Sollicitudo rei Socialis of the Supreme Pontiff John Paul II for the twentieth Anniversary of Populorum Progressio. Vatican: Libreria Editrice Vaticana.
MLA
John Paul II, . Encyclical Letter Sollicitudo rei Socialis of the Supreme Pontiff John Paul II for the twentieth Anniversary of Populorum Progressio. Vatican: Libreria Editrice Vaticana. 1987.
