APA (7th ed.) Citation

Darwin Charles. (1952). The origin of species by means of natural selection. Enciclopaedia Britannica.

Chicago Style (17th ed.) Citation

Darwin Charles. The Origin of Species by Means of Natural Selection. Chicago: Enciclopaedia Britannica, 1952.

MLA (9th ed.) Citation

Darwin Charles. The Origin of Species by Means of Natural Selection. Enciclopaedia Britannica, 1952.