APA (7th ed.) Citation

Wolff, R. P. (2006). About philosophy (9th ed.). Prentice Hall.

Chicago Style (17th ed.) Citation

Wolff, Robert Paul. About Philosophy. 9th ed. Upper Saddle River, NJ: Prentice Hall, 2006.

MLA (9th ed.) Citation

Wolff, Robert Paul. About Philosophy. 9th ed. Prentice Hall, 2006.

Warning: These citations may not always be 100% accurate.