Παραπομπή σε μορφή APA (7η εκδ.)

Spencer, H. (1993). The Principles of Ethics: By Herbert Spencer. Williams and Norgate.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Spencer, Herbert. The Principles of Ethics: By Herbert Spencer. London ; Edinburgh: Williams and Norgate, 1993.

Παραπομπή σε μορφή MLA (8th εκδ.)

Spencer, Herbert. The Principles of Ethics: By Herbert Spencer. Williams and Norgate, 1993.