APA (7th ed.) Citation

Darwin, C., Barrett, P. H., & Freeman, R. B. (1989). The descent of man, and selection in relation to sex, 2. Pickering.

Chicago Style (17th ed.) Citation

Darwin, Charles, Paul H. Barrett, and R. B. Freeman. The Descent of Man, and Selection in Relation to Sex, 2. London: Pickering, 1989.

MLA (8th ed.) Citation

Darwin, Charles, et al. The Descent of Man, and Selection in Relation to Sex, 2. Pickering, 1989.