The principles of psychology /
by Herbert Spencer.

APA Citation

Spencer, H., Collins, F. Howard (Frederick Howard). (1892). The principles of psychology. New York: D. Appleton and company.

MLA Citation

Spencer, Herbert, 1820-1903, and F. Howard (Frederick Howard) Collins. The Principles of Psychology. New York: D. Appleton and company, 1892.

Warning: These citations may not always be complete (especially for serials).