APA (7th ed.) Citation

Darwin, C. The Foundations of the Origin of Species Two Essays written in 1842 and 1844.

Chicago Style (17th ed.) Citation

Darwin, Charles. The Foundations of the Origin of Species Two Essays Written in 1842 and 1844.

MLA (9th ed.) Citation

Darwin, Charles. The Foundations of the Origin of Species Two Essays Written in 1842 and 1844.

Warning: These citations may not always be 100% accurate.