Index Librorum Prohibitorum (1900) [Index of Prohibited Books of Pope Leo XIII (1900)] (in Latin). Vatican. 1900. p. 298. Retrieved 2 August 2009. index librorum prohibitorum tricassinus.
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Indice de Libros Prohibidos (1877) [Index of Prohibited Books of Pope Pius IX (1877)] (in Spanish). Vatican. 1880. Retrieved 2 August 2009.