Kropotkin, P. (1924). Ethics: Origin and development. London: Harrap & Co.
Cita Chicago (17th ed.)Kropotkin, Peter. Ethics: Origin and Development. London: Harrap & Co, 1924.
Cita MLA (8th ed.)Kropotkin, Peter. Ethics: Origin and Development. London: Harrap & Co, 1924.
Atenció: Aquestes cites poden no estar 100% correctes.