"Leggi sulle fonti del diritto" [Read about the sources of law] (in Italian). The Vatican. 1 October 2008. Art. 1, (item) 2.
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One or more of the preceding sentences incorporates text from a publication now in the public domain: Herbermann, Charles, ed. (1907). "Acta Sanctæ Sedis". Catholic Encyclopedia. Vol. 1. New York: Robert Appleton Company.