Coppa, F. J. (1979). Pope Pius ix: Crusader in a secular age. Twayne.
Chicago-čujuhus (17. p.)Coppa, Frank J. Pope Pius Ix: Crusader in a Secular Age. Boston: Twayne, 1979.
MLA-čujuhus (9. p.)Coppa, Frank J. Pope Pius Ix: Crusader in a Secular Age. Twayne, 1979.
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