Darwin, C. (1990). On the origin of species by means of natural selection, or the preservation of favored races in the struggle for life. Project Gutenberg.
Chicago-Zitierstil (17. Ausg.)Darwin, Charles. On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life. Champaign, Ill: Project Gutenberg, 1990.
MLA-Zitierstil (9. Ausg.)Darwin, Charles. On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life. Project Gutenberg, 1990.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.