APA

Darwin C. R., . (1909). The origin of species. New York: Literary Classics, Inc.

Chicago

Darwin Charles Robert, . 1909. The origin of species. New York: Literary Classics, Inc.

Harvard

Darwin C. R., . (1909). The origin of species. New York: Literary Classics, Inc.

MLA

Darwin Charles Robert, . The origin of species. New York: Literary Classics, Inc. 1909.