Catholic Church. Pope (1958-1963 : John XXIII) & Gibbons, W. J. (1961). Mater et magistra: Encyclical letter of His Holiness Pope John XXIII: Christianity and social progress. Paulist Press.
Παραπομπή σε μορφή Chicago (17η εκδ.)Catholic Church. Pope (1958-1963 : John XXIII) και William J. Gibbons. Mater Et Magistra: Encyclical Letter of His Holiness Pope John XXIII: Christianity and Social Progress. New York: Paulist Press, 1961.
Παραπομπή σε μορφή MLA (8th εκδ.)Catholic Church. Pope (1958-1963 : John XXIII) και William J. Gibbons. Mater Et Magistra: Encyclical Letter of His Holiness Pope John XXIII: Christianity and Social Progress. Paulist Press, 1961.
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