Darwin, C. The origin of species by means of natural selection or the preservation of favored races in the struggle for life and the descent of man and selection in relation to sex. New York: The Modern Library.

Darwin, Charles. The Origin of Species By Means of Natural Selection or the Preservation of Favored Races in the Struggle for Life and the Descent of Man and Selection in Relation to Sex. New York: The Modern Library.

Darwin, Charles. The Origin of Species By Means of Natural Selection or the Preservation of Favored Races in the Struggle for Life and the Descent of Man and Selection in Relation to Sex. New York: The Modern Library.