APA način citiranja (7. izdanje)
Richards, R. J. (2008). The tragic sense of life: Ernst Haeckel and the struggle over evolutionary thought. University of Chicago Press.
Čikaški stil citiranja (17. izdanje)
Richards, Robert J. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought. Chicago: University of Chicago Press, 2008.
MLA način citiranja (9. izdanje)
Richards, Robert J. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought. University of Chicago Press, 2008.
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