Coppa, F. J. (1979). Pope Pius ix: Crusader in a secular age. Twayne.
Cita Chicago Style (17a ed.)Coppa, Frank J. Pope Pius Ix: Crusader in a Secular Age. Boston: Twayne, 1979.
Cita MLA (9a ed.)Coppa, Frank J. Pope Pius Ix: Crusader in a Secular Age. Twayne, 1979.
Precaución: Estas citas no son 100% exactas.