Cita APA (7a ed.)

Richards, R. J. (2008). The tragic sense of life: Ernst Haeckel and the struggle over evolutionary thought. University of Chicago Press.

Cita Chicago Style (17a ed.)

Richards, Robert J. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought. Chicago: University of Chicago Press, 2008.

Cita MLA (8a ed.)

Richards, Robert J. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought. University of Chicago Press, 2008.