APA (7th ed.) Citation

Wolff, R. P. (1989). About philosophy (4th ed.). Prentice Hall.

Chicago Style (17th ed.) Citation

Wolff, Robert Paul. About Philosophy. 4th ed. Englewood Cliffs, N.J: Prentice Hall, 1989.

MLA (9th ed.) Citation

Wolff, Robert Paul. About Philosophy. 4th ed. Prentice Hall, 1989.