APA (7th ed.) Citation

Spencer, H. The Principles of Biology, Volume 1 (of 2).

Chicago Style (17th ed.) Citation

Spencer, Herbert. The Principles of Biology, Volume 1 (of 2).

MLA (9th ed.) Citation

Spencer, Herbert. The Principles of Biology, Volume 1 (of 2).

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