APA (7th ed.) Citation

Spencer, H. (1890). The principles of psychology (3rd ed.). Williams and Norgate.

Chicago Style (17th ed.) Citation

Spencer, Herbert. The Principles of Psychology. 3rd ed. London: Williams and Norgate, 1890.

MLA (9th ed.) Citation

Spencer, Herbert. The Principles of Psychology. 3rd ed. Williams and Norgate, 1890.

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