APA-referens (7:e uppl.)

Haeckel, E., & McCabe, J. (1905). The wonders of life: A popular study of biological philosophy. Harper & brothers.

Chicago-referens (17:e uppl.)

Haeckel, Ernst, och Joseph McCabe. The Wonders of Life: A Popular Study of Biological Philosophy. New York, London: Harper & brothers, 1905.

MLA-referens (8:e uppl.)

Haeckel, Ernst, och Joseph McCabe. The Wonders of Life: A Popular Study of Biological Philosophy. Harper & brothers, 1905.