Cita APA (7a ed.)

Darwin, C. (1996). The origin of species by means of natural selection: The descent of man and selection in relation to sex (2nd ed., 6th pr.). Encyclopedia Britannica.

Cita Chicago Style (17a ed.)

Darwin, Charles. The Origin of Species by Means of Natural Selection: The Descent of Man and Selection in Relation to Sex. 2nd ed., 6th pr. Chicago [etc.]: Encyclopedia Britannica, 1996.

Cita MLA (9a ed.)

Darwin, Charles. The Origin of Species by Means of Natural Selection: The Descent of Man and Selection in Relation to Sex. 2nd ed., 6th pr. Encyclopedia Britannica, 1996.