First principles

MLA

Spencer, Herbert. First Principles. 6th and final ed. (rev. by the author) London: Williams & Norgate, 1928.

APA

Spencer, H. (1928). First principles. 6th and final ed. (rev. by the author) London: Williams & Norgate.

Chicago

Spencer, Herbert, First Principles. 6th and final ed. (rev. by the author) London: Williams & Norgate, 1928.