Cita APA (7a ed.)

Poppelbaum, H., & Barfield, O. (1960). Man and Animal: Their essential difference (2nd ed.). Anthroposophical Publishing.

Cita Chicago Style (17a ed.)

Poppelbaum, Hermann, y Owen Barfield. Man and Animal: Their Essential Difference. 2nd ed. London: Anthroposophical Publishing, 1960.

Cita MLA (9a ed.)

Poppelbaum, Hermann, y Owen Barfield. Man and Animal: Their Essential Difference. 2nd ed. Anthroposophical Publishing, 1960.