APA (7th ed.) Citation

Spencer, H. (1913). The principles of psychology. D. Appleton and company.

Chicago Style (17th ed.) Citation

Spencer, Herbert. The Principles of Psychology. New York, London: D. Appleton and company, 1913.

MLA (9th ed.) Citation

Spencer, Herbert. The Principles of Psychology. D. Appleton and company, 1913.