APA (7th ed.) Citation

Spencer, H. (1970). The principles of psychology. Gregg International Publishers Limited.

Chicago Style (17th ed.) Citation

Spencer, Herbert. The Principles of Psychology. Farnham: Gregg International Publishers Limited, 1970.

MLA (9th ed.) Citation

Spencer, Herbert. The Principles of Psychology. Gregg International Publishers Limited, 1970.

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