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APA citation. Periodi. (1911). In The Catholic Encyclopedia. New York: Robert Appleton Company. http://www.newadvent.org/cathen/11669a.htm
MLA citation. "Periodi." The Catholic Encyclopedia. Vol. 11. New York: Robert Appleton Company, 1911. <http://www.newadvent.org/cathen/11669a.htm>.
Ecclesiastical approbation. Nihil Obstat. February 1, 1911. Remy Lafort, S.T.D., Censor. Imprimatur. +John Cardinal Farley, Archbishop of New York.
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