APA (7th ed.) Citation

Haeckel, E., & McCabe, J. (2004). The Evolution of Man - Volume 1. Project Gutenberg.

Chicago Style (17th ed.) Citation

Haeckel, Ernst, and Joseph McCabe. The Evolution of Man - Volume 1. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Haeckel, Ernst, and Joseph McCabe. The Evolution of Man - Volume 1. Project Gutenberg, 2004.

Warning: These citations may not always be 100% accurate.