APA (7th ed.) Citation

Darwin, C. (1872). The Origin of species (6th ed.). 0.U.Pr.

Chicago Style (17th ed.) Citation

Darwin, Charles. The Origin of Species. 6th ed. London: 0.U.Pr, 1872.

MLA (9th ed.) Citation

Darwin, Charles. The Origin of Species. 6th ed. 0.U.Pr, 1872.