Shaw (Ph.D), Jeffrey M.; Demy (Ph.D), Timothy J. (27. mars 2017). «Pacem, Dei Munus Pulcherrimum, a Papal Encyclical Issued by Pope Benedict (May 23, 1920)». War and Religion: An Encyclopedia of Faith and Conflict [3 volumes] (på engelsk). ABC-CLIO. s. 928. ISBN9781610695176. «Pacem, Dei Munus Pulcherrimum (Peace, Beautiful Gift of God) is a papal encyclical on peace and Christian reconciliation delivered by Pope Benedict XV (r. 1914-1922) at St. Peter's, Rome (---). This encyclical was an attempt by the Vatican to reassert itself into the affairs of Europe and the world. The Vatican was not invited to participate in the deliberations leading to the Treaty of Versailles, which brought the First World War to an end, nor was there any Vatican involvement in the formation of the new League of Nations.»
Smestad Jr., John R. «Europe 1914–1945: Attempts at Peace». The Student Historical Journal 1994–1995. Loyola University New Orleans. Arkivert fra originalen 7. desember 2021. Besøkt 4. oktober 2019.
Smestad Jr., John R. «Europe 1914–1945: Attempts at Peace». The Student Historical Journal 1994–1995. Loyola University New Orleans. Arkivert fra originalen 7. desember 2021. Besøkt 4. oktober 2019.
