Darwin, C. (1996). The origin of species by means of natural selection: The descent of man and selection in relation to sex (2nd, 6th print.). Encyclopædia Britannica.
Citazione stile Chigago Style (17a edizione)Darwin, Charles. The Origin of Species by Means of Natural Selection: The Descent of Man and Selection in Relation to Sex. 2nd, 6th print. Chicago: Encyclopædia Britannica, 1996.
Citatione 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, 6th print. Encyclopædia Britannica, 1996.
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