APA (7th ed.) Citation

Darwin, C., & Ridley, M. (1986). The essential Darwin. Unwin Hyman.

Chicago Style (17th ed.) Citation

Darwin, Charles, and Mark Ridley. The Essential Darwin. London: Unwin Hyman, 1986.

MLA (9th ed.) Citation

Darwin, Charles, and Mark Ridley. The Essential Darwin. Unwin Hyman, 1986.

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