Catholic Church. Pope (1878-1903 : Leo XIII) & Leo XIII, P. (1998). Encyclical letter Libertas praestantissimum of the supreme Pontiff Leo XIII: On human liberty, June 20, 1888. Angelus Press.
Chicago Style (17th ed.) CitationCatholic Church. Pope (1878-1903 : Leo XIII) and Pope Leo XIII. Encyclical Letter Libertas Praestantissimum of the Supreme Pontiff Leo XIII: On Human Liberty, June 20, 1888. Kansas City, Mo.: Angelus Press, 1998.
MLA (8th ed.) CitationCatholic Church. Pope (1878-1903 : Leo XIII) and Pope Leo XIII. Encyclical Letter Libertas Praestantissimum of the Supreme Pontiff Leo XIII: On Human Liberty, June 20, 1888. Angelus Press, 1998.
Warning: These citations may not always be 100% accurate.