APA (7th ed.) Citation

Spencer, H. (1898). The principles of biology. D. Appleton.

Chicago Style (17th ed.) Citation

Spencer, Herbert. The Principles of Biology. New York: D. Appleton, 1898.

MLA (9th ed.) Citation

Spencer, Herbert. The Principles of Biology. D. Appleton, 1898.

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