Cita APA (7th ed.)
Spencer, H. (1875). System der synthetischen Philosophie.
Cita Chicago (17th ed.)
Spencer, Herbert. System Der Synthetischen Philosophie. Stuttgart, 1875.
Cita MLA (9th ed.)
Spencer, Herbert. System Der Synthetischen Philosophie. 1875.
Atenció: Aquestes cites poden no estar 100% correctes.