The principles of sociology,
by Herbert Spencer.

APA Citation

Spencer, H. (18991905). The principles of sociology. 3d ed. New York: D. Appleton and Company.

MLA Citation

Spencer, Herbert, 1820-1903. The Principles of Sociology. 3d ed. New York: D. Appleton and Company, 18991905.

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