Barcalow, E. (2001). Open questions: An introduction to philosophy (3rd ed.). Wadsworth/Thomson Learning.
Cita Chicago (17th ed.)Barcalow, Emmett. Open Questions: An Introduction to Philosophy. 3rd ed. Australia: Wadsworth/Thomson Learning, 2001.
Cita MLA (9th ed.)Barcalow, Emmett. Open Questions: An Introduction to Philosophy. 3rd ed. Wadsworth/Thomson Learning, 2001.
Atenció: Aquestes cites poden no estar 100% correctes.