Darwin, C. (1872). The Origin of species (6th ed.). 0.U.Pr.
Cita Chicago Style (17a ed.)Darwin, Charles. The Origin of Species. 6th ed. London: 0.U.Pr, 1872.
Cita MLA (9a ed.)Darwin, Charles. The Origin of Species. 6th ed. 0.U.Pr, 1872.
Precaución: Estas citas no son 100% exactas.